Hi Adolfo,
The IAP's will be part of a group on Central.
When you create a group, it will ask you for setting up a group password. Once the IAP is moved to this group, the group password is used as login credentials for the IAP.
In case you need to change them, use the following steps:
1. Navigate to the group.
2. Select wireless management.
3. Click on System
4. Administration.
I have attached the screenshot for reference.
In my case IAP is on a group named TAC.