Dear respected Yacine B,
Good day! Thank you for posting to Microsoft Community. We are happy to help you.
As per your description, it seems that you cannot find the option to install Office 365 suit.
If my understanding is right, for the situation you encountered, there is two reasons why you cannot see the "Install" button when you go to Office 365 portal account using your school account.
Reason 1:
As not all Office 365 Education subscription account include Office desktop client license. For example, if your Office 365 education (A1 for student) account doesn’t contain the license “The latest desktop version of Office” and that's why you cannot see use Office desktop client app on your pc.
To check whether your account have the right license, please first follow the steps below to check that you have been assigned the right Office license to verify it:
1. Log in to Office 365 portal (www.office.com)
2. Settings>Office 365>Subscriptions
3. Under Licenses section, check you have been assigned the “The latest desktop version of Office”.
If it shows" Office for the web" you can edit/use only Office Online if you have this license. If you don't have “The latest desktop version of Office” license, if you don’t have this license, it means that you cannot install Office suit. You may need to contact your Office 365 admin to assign the related license to you.
Reason 2:
And if you have such license, we’d suggest you contact your Office admin to check if they have disabled the option to install Office 365 suit. As shown below:

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For how to find your office 365 admin, you can check this article: How do I find my Microsoft 365 admin? - Microsoft Support
We appreciate your understanding that sometimes the initial suggestions may not resolve the problem very soon. However, we can work together to narrow down and resolve the situation. So, please kindly provide more information below to let us work further.
1.May I know if the other colleagues have the same problem?
2.Could you go to Subscriptionand provide the screenshot of it.
Appreciate your patience and understanding and thank you for your time and cooperation.
Sincerely,
Waqas Muhammad