Honestly, the most complicated part is getting the install media ready to go.

Once the installer starts, you’re just answering prompts like the local username and password you want, language and keyboard layout, and time zone, and it does the rest on its own.

Then the computer reboots, and you end up on the desktop of a fully usable computer. Most distros will have a one-time popup welcoming you and maybe leading you to some Flatpak “store” where you can search for free apps to install.