While on your Chromebook, you can push CTRL + ALT + ? on the keyboard at any time to access popular shortcuts or search for keyboard shortcuts.
The entire list of Chrome shortcuts can be viewed here: Chromebook Keyboard Shortcuts
Some commonly used shortcuts are:
Copy: CTRL + C
Paste: CTRL + V
Caps Lock: ALT + Search
Screenshot: CTRL + Switch Window (whole page) CTRL + Shift + Switch Window (Part of a page)