I think this is what you're asking - Keep the iPhone display on longer?
Start with the home screen:

Click on the grey gear-like Settings icon at the lower right-ish part of the list of icons. Then do what the instructions above say.
I hope this helps.
Good luck!
Cheers,
Scott.
Start with the home screen:

Click on the grey gear-like Settings icon at the lower right-ish part of the list of icons. Then do what the instructions above say.
I hope this helps.
Good luck!
Cheers,
Scott.