[SOLVED] Setting ADC and timer clock input (16f877a)

[Snitch]

I'm new to PIC programming.
Can someone please tell me what are the factors that I should be concerned about when setting ADC and timer clock inputs. I have given a project to complete but this is not my study area. I'm learning everything from the beginning. I've written the code but I need it to be accurate. I'm using CCS C.

Thanks in advance