Installed opencart-3.0.3.1

1. I am able to add a product to the cart, and checkout and see the pay procedure.
2. Install pavilion_v.2.3.2 (followed the instructions to the letter), and changed to minimal Pavilaion theme, red skin.
3. Unable to see cart or checkout even if I add new product.

Only way to resolve it is to then go to extensions, themes
1. Uninstall Pavilion Theme
2. Uninstall Default Theme
3. Reinstall Default Theme
4. Reinstall Pavilion Theme

This has been an issue for so long!! Come on when are you fixing this??