Everything you need to setup the registers is really in the pdf of your chip. Please be careful selecting new chips as Microchip may issue a Preliminary pdf file having a lot of errors. Also keep your eye on the errata files that Microchip publishes on the chip's page.

Now, you asked for more precision on your first post.

Most chips have 8 or 10 bits at the low end 8-bit chips. If you can spare some time on your chip and your application, then you may use the Oversampling routine published here: http://dt.picbasic.co.uk/CODEX/AnalogueOverSampling

You may reach 16-bits results given you will sacrifice 50-100ms, depending on the chip. I thing 12 or 14 bits are good enough with maximum 6.2ms delay in your program (less if you have a fast MCU).

With the routine mentioned, you do not need to filter your results for noise or invalid sampling.

Ioannis