I remember using sudo previously, but I thought it was a permanent command that I wouldn't need to enter every time.
Nope
The "life" on sudo is usually about 5 minutes, then you need to use it again.
There are also different levels of elevated privileges attaching to certain commands, such that you need to use sudo each time you use them, even if only moments apart.
As an example if you were to run
and you were to find only 3 updates available that were small and quick to install, you would still have to run (my comments preceded by a hash)
Code:
sudo apt upgrade
#NOT
apt upgrade
You learn these with experience, and there is probably a list out there in cyberspace.
Is there a Linux book for dummies?
There is, actually.
If you Google up (or search engine of your choice)
linux for dummies
you will find there is Linux for Dummies 9th edition available at Amazon. Actually, looks like there is a 10th edition.
The first entry in my search said about Linux for Dummies cheat sheet, and scrolling through that makes for a good read, albeit about Ubuntu, perhaps copy, paste and save it?
HTH
Wizard
BTW - I haven't read the Dummies book, I'm just a dummy with a title who has gathered a lot of experience.