This page explains it quite clearly I think:
First of all it depends whether you opted to pay tax along with your social charges, or whether you don't.
Then it depends whether your income is from sales, services or professional activities.
If you have already paid income tax at a fixed rate along with your other charges, you want page 1, boxes 5TA, 5TB or 5TE. If you're declaring untaxed income you want page 2, seems to be 5KO, 5KP or 5HQ.
The figure you declare is your total turnover between 1.1.16 and 31.12.16, which obviously should be the total of your 4 quarterly declarations that you submitted. You may have been sent a statement by URSSAF or RSI confirming what this figure is, or you may be able to download an attestation from your espace client, or failing that, just use your own records and make sure the figures correspond.
Hope this helps.