After you accepted the invitation you can communicate with the customer using the Project Message Board, which becomes available for viewing and posting messages only to the customer and the selected provider.
The customer can unilaterally confirm the budget of your project before the contract is signed.
After you have discussed all the project details with the customer, both you and the customer have to sign the contract.
The customer is the first to sign the contract. Then he has to wait for you to sign the contract. You will receive the corresponding notification in your Personal message board and to your e-mail. To sign the contract, open the current project in My Office -> View Projects and click "Sign contract". Read the terms, check the box "I agree to the terms of the contract" and click "Sign contract".
After both parties have signed the contract the customer is expected to post the escrow deposit.
Posting the deposit means that the project work has started in the system.