How can i approve sales agreement already submitted, if it's not displayed in pending approval page?

After having created and submitted the contract (sales contract), how can i approve it?

what are the steps to follow? What roles do i need?

Once approved the contract, i'll see sales agreement automatically populated when i create a sale order in sales order page, or do i need some setups ?

If i do, can you please give me the list of what to do ?

Thank you,

Christian