That's their info page for merchants.
I see one problem still. You can't just add paypal to your site without having a contract with them to handle the flow of money. And you might be hired as a web-programmer (which seems rather remarkable, by the way, because you say you don't have the needed experience), but I assume you're not authorized to sign the necessary contracts with them. That's a job for the CFO (chief financial officer).
Once the contract is signed, I'm sure paypal will give you all information and support necessary to implement it. After all, youer company is their customer, and they make money from it, so it's in their interest to help.
Hope this helps.
Kees

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic