Does anyone have any suggestions on how to use Indirect function?

Under column AC, INDIRECT("AC"&591+1) in cell AC593.
When I copy this cell to the right under column AD, does anyone have any
suggestions on keeping the "AC" changing based on located column?
This is what I want under column AD, INDIRECT("AD"&591+1) in cell AC593.
Does anyone have any suggestions?
Thanks in advance for any suggestions
Eric