If you want to use the speedy keyboard shortcuts in Gmail then you need to turn them on first. Here is how to do it in 5 steps:

1) Click the Settings gear on the right side in your Gmail toolbar.
settings gear
2) Select Settings from the menu that appears.

Gmail settings1
3) Select the the General tab.

General Tab

 

4) Scroll down until you find Keyboard shortcuts. Check Keyboard shortcuts on.

Keyboard shortcuts on
5) Don’t forget to  click Save Changes at the bottom of the page.

 

Read about my favorite Gmail and Chrome shortcuts!