diff --git a/docs.it4i/general/applying-for-resources.md b/docs.it4i/general/applying-for-resources.md
index 165d31707ab512befbdac6665ead1e77c5892219..6fb2b0e4b187ac744b9c7eac188217bef38630c1 100644
--- a/docs.it4i/general/applying-for-resources.md
+++ b/docs.it4i/general/applying-for-resources.md
@@ -12,11 +12,147 @@ The computational resources of IT4I are allocated by the Allocation Committee vi
 
 In all cases, IT4Innovations’ access mechanisms are aimed at distributing computational resources while taking into account the development and application of supercomputing methods and their benefits and usefulness for society. The applicants are expected to submit a proposal. In the proposal, the applicants **apply for a particular amount of core-hours** of computational resources. The requested core-hours should be substantiated by scientific excellence of the proposal, its computational maturity and expected impacts. The allocation decision is based on the scientific, technical, and economic evaluation of the proposal.
 
-For more information, see [Computing resources allocation][a] and [Obtaining Login Credentials][1].
+## Becoming Primary Investigator
+
+The Primary Investigator (PI) is authorized to use the clusters by the decision issued by the Allocation Committee. The PI will be informed by IT4I about the Allocation Committee decision.
+
+## Authorize Collaborators for Your Project
+
+As a PI, you can approve or deny users' requests to join your project.
+
+### Authorization by Web
+
+This is a preferred method if you have an IT4I or e-INFRA CZ account.
+
+Log in to the [IT4I SCS portal][e] using IT4I credentials and go to the **Authorization Requests** section. Here you can authorize collaborators for your project.
+
+### Authorization by Email (An Alternative Approach)
+
+In order to authorize a Collaborator to utilize the allocated resources, the PI should contact the [IT4I support][f] (email: [support\[at\]it4i.cz][g]) and provide the following information:
+
+1. Identify their project by project ID.
+1. Provide a list of people, including themself, who are authorized to use the resources allocated to the project. The list must include the full name, email and affiliation. If collaborators' login access already exists in the IT4I systems, provide their usernames as well.
+1. Include "Authorization to IT4Innovations" into the subject line.
+
+!!! warning
+    Should the above information be provided by email, the email **must be** digitally signed. Read more on [digital signatures][2] below.
+
+Example (except the subject line which must be in English, you may use Czech or Slovak language for communication with us):
+
+```console
+Subject: Authorization to IT4Innovations
+
+Dear support,
+
+Please include my collaborators to project OPEN-0-0.
+
+John Smith, john.smith@myemail.com, Department of Chemistry, MIT, US
+Jonas Johansson, jjohansson@otheremail.se, Department of Physics, RIT, Sweden
+Luisa Fibonacci, lf@emailitalia.it, Department of Mathematics, National Research Council, Italy
+
+Thank you,
+PI
+(Digitally signed)
+```
+
+!!! note
+    Web-based email interfaces cannot be used for secure communication; external application, such as Thunderbird or Outlook must be used. This way, your new credentials will be visible only in applications that have access to your certificate.
+
+### Process Flow Chart
+
+This chart describes the process of obtaining login credentials on the clusters. You may skip the tasks that you have already done. Some of the tasks, marked with asterisk (\*), are clickable and will take you to a more detailed description.
+
+* I am a collaborator on a project and want to obtain login credentials
+
+<div class="mermaid">
+graph TB
+id10(I am a collaborator on a project and want to obtain login credentials)
+id20[Obtain a certificate for digital signature]
+id10-->id20
+id30[EduID organizations from CESNET*]
+click id30 "#certificates-for-digital-signatures"
+id40[Personal certificate from PostSignum or I.CA]
+id50[Free certificate from Sectigo / Comodo*]
+click id50 "#alternative-way-to-personal-certificate"
+id55[Other trusted certificate]
+subgraph ""
+id20-->id30
+id20-->id40
+id20-->id50
+id20-->id55
+end
+id60[Export and save the certificate to a file]
+id30-->id60
+id40-->id60
+id50-->id60
+id55-->id60
+id70[Import the certificate into your email client*]
+click id70 "#installation-of-the-certificate-into-your-mail-client"
+id60-->id70
+id80[Send an email with request for access to IT4I Support*]
+click id80 "#login-credentials"
+id70-->id80
+</div>
+
+* I am a Primary Investigator and I want to allow my collaborators to access my project
+
+<div class="mermaid">
+graph TB
+id110(I am a Primary Investigator and I want to allow my collaborators to access my project)
+id120[Obtain a certificate for digital signature]
+id110-->id120
+id130[EduID organizations from CESNET*]
+click id130 "#certificates-for-digital-signatures"
+id140[Personal certificate from PostSignum or I.CA]
+id150[Free certificate from Sectigo / Comodo*]
+click id150 "#alternative-way-to-personal-certificate"
+id155[Other trusted certificate]
+subgraph ""
+id120-->id130
+id120-->id140
+id120-->id150
+id120-->id155
+end
+id160[Export and save the certificate to a file]
+id130-->id160
+id140-->id160
+id150-->id160
+id155-->id160
+id170[Import the certificate into your email client*]
+click id170 "#installation-of-the-certificate-into-your-mail-client"
+id160-->id170
+id180[Send an email with request for authorization to IT4I Support*]
+click id180 "#authorization-by-e-mail-an-alternative-approach"
+id170-->id180
+</div>
+
+* I am an existing user/Primary Investigator and I want to manage my projects/users
+
+<div class="mermaid">
+graph TB
+id210(I am an existing user/Primary Investigator and I want to manage my projects/users)
+id220[Log into scs.it4i.cz]
+id230[Go to the Authorization Requests section]
+id210-->id220
+id220-->id230
+id240[Submit a request to become a project member]
+id245[Wait for an approval from the Primary Investigator]
+id230-->|User|id240
+id240-->id245
+id250[Wait for a user to submit the request to become a project member]
+id255[Approve or deny user requests for becoming project members]
+id230-->|Primary Investigator|id250
+id250-->id255
+id240-.->id255
+</div>
 
 [1]: obtaining-login-credentials/obtaining-login-credentials.md
+[2]: https://docs.it4i.cz/general/obtaining-login-credentials/obtaining-login-credentials/#certificates-for-digital-signatures
 
 [a]: https://www.it4i.cz/en/for-users/computing-resources-allocation
 [b]: http://www.it4i.cz/open-access-competition/?lang=en&lang=en
 [c]: http://www.it4i.cz/obtaining-computational-resources-through-directors-discretion/?lang=en&lang=en
 [d]: https://prace-ri.eu/hpc-access/deci-access/deci-access-information-for-applicants/
+[e]: https://scs.it4i.cz
+[f]: https://support.it4i.cz/rt/
+[g]: mailto:support@it4i.cz