When the application you filed is accepted, you will be notified about a new task to confirm the assignment (see How to complete a task). You can then either follow the path of completing a task or go to Assignments under View section of the top menu and selecting the assignment you want to manage.
Note that you can only manage the assignments with Confirmation pending status.
Click the selected assignment to view its details.
Now, select the relevant revision and after reviewing its details, decide whether you would like to accept or reject it.
You will be then prompted to confirm your action. There will also be a possibility to leave a comment for the contractor. To finalize and send your decision to the contractor click Yes.