Click DealScope_User name

Click Manage Assignments to add users

Click Add Assignment to add users

Select all users you want to give access to DealScope.
If a user is not visible here, change the list view -- for example, to Recently Viewed.
Click Next

The preferable choice here is "No expiration date".
Click Assign

Open any Opportunity page. Then click the gear icon in the top menu and select Edit Page

Find the aiSummaryPanel component and drag it to the desired place on the page. Then click Save, and then Back.
Important: the page must be a Lightning Web Component (LWC) page. If it is not, you will need to convert it to LWC first.
Adding DealScope to a Lead page works the same way.