The number next to the letter symbol in the upper right-hand corner shows you the number of unread emails you have (a).
You can open your inbox in a new tab by clicking on your email address (b).
If you want to check your inbox for new emails manually, click on the refresh symbol (c).
If you want to compose an email, click on the pen symbol (d).
By clicking on the arrow symbol next to the pen symbol, you can open and close the drop-down menu.
If you want to change your settings, click on the gear symbol (e).