Dear Adewale Abobarin ,

please go to your profile page*) and click onto the 'edit' button just right to your name at the upper left of that page.

In the drop down menue, which is then opened, there is the affiliation button...

('Edit primary affiliation and location')

Do not forget to save your changes...

Please see also:

https://help.researchgate.net/hc/en-us/articles/14292743587601-Your-institution-and-department

*) you can access your profile page by just clicking onto your name in this answer

Good luck and

best regards

G.M.