There are thousands of things to do, namely configuring all the software that you need to run on your computer. Of course, that varies depending on your use case and cannot be fully described here - check the respective sections on software configuration.
Also, there are hundreds of lists available in the internet, just use the appropriate google search:
https://www.google.com/search?q=things+to+do+after+ubuntu+20.04+installation
I liked these:
Besides that, there are a few things I always do:
sudo apt update && sudo apt upgrade
sudo apt install ubuntu-restricted-extras
sudo apt install gnome-tweaks
sudo apt install gnome-shell-extensions
sudo apt install chrome-gnome-shell
ls -l ~/.local/share/gnome-shell/extensions/
Relevant/interesting gnome-extensions:
— Jonas Rathert 2021/11/23 21:09