OK, here is what I do understand,

for ADCON1 control register.....I need...

bit 7 = 0
bit 6 = 0
bit 5 = 1 'I am using Vref- AN2
bit 4 = 1 ' I am using Vref+ AN3

what I still don't understand....from page 224

bit 3 = ?
bit 2 = ?
bit 1 = ?
bit 0 = ?