After login you will see your name on the top right side. Click on it and select dashboard. Here you will see an exhaustive menu and practically you can do everything here.
As already told in the response by a member above, you have to give a 4 digit PIN number of your choice which you have to mention in your invoice also. This is a fixed number and remember it as you will have to give it in your invoices every time.
You can go to 'My profile' and see your details, contributions so far, awards and cash payments so far etc. Everywhere you will find some useful hyperlinks and you can reach those places quickly.
You can go to 'Scoreboard (new)' and see your contributions under different categories.
In dashboard, you will be seeing your current alerts and contribution snippets on the right side and you can see all of them by clicking on more.
So try to explore the dashboard and you will find a lot of information there.
Knowledge is power.