Manual Failover

Hello Engineers,
I am facing an issue with the manual failover of the standby to the master
role. I was able to promote the standby and got it out of recovery mode.
How do I direct applications to point to the standby which has assumed the
role of the current master, and what should I do after completing
maintenance on the previous master to assume its original role as master?
I would appreciate any input, and thank you for your time.

Yongye Serkfem