Metadata can be edited using keyboard shortcuts:
Add (Insert): CTRL + I
adding a new Layer
Edit: CTRL + E
start editing
Save: CTRL + S
save your edits
Paging: ALT + arrow left / arrow right
open the next or the previous item
On Apple devices use Apple Key instead of CTRL.
https://www.youtube.com/watch?v=S5I7IWyqy84&t=8s