I can not to edit the Woocommerce shop page

I have some of the issue about to edit Woocommerce shop page:
1. How to edit the shop page template with admin account? the admin backend top button "Upfront" or "Modify current theme"?
2. I have been to try both of the method like above, but it is not working when I changed the top
3. I have been test Spirit and Fixer themes, the same as "2".
4. I can see the shop page frontend well.