Here's one.
https://ubuntu.com/tutorials/command-line-for-beginners

Any command in your path
echo $PATH

-that is executable, will run.
The default includes /bin, /usr/bin and others.
You can create a bin directory in your HOME for personal stuff.

But this might be beyond you until you master the basics, which I recommend.

Otherwise, click on icons like Mac and windows users do. Apps do get installed in "start" menus, but let the package manager do that for you.

You can't skip the basics! It's like driving a car without driver training. Very confusing.

Good luck. Now "hit the books" or web tutorials.

NOW

Time spent learning will be repaid exponentially!
I built a whole damn career teaching myself stuff.

Good luck and happy hacking.

learned that a long time ago.

(provided the file is actually an executable) can be executed regardless of the extension or lack of an extension.

It’s kinda hard to explain and it’s been a long time but all files in Unix/Linux have 3 sets of permissions: for the owner, for the group, and for anybody. They are formatted in those 3 “groups” with 3 available permissions for each: read, write, and execute…done in binary, where (if I recall correctly) read has a value of 1, write has a value of 2, and execute has a value of 4.

So, for example, if a file was to be readable, writable, and executable by anyone, the permissions would be set to 777.

If the file was to be only readable, writable, and executable by the owner, the permissions would be set to 700.

Now that I’ve totally fucked you up, read the man pages.

and can repurpose "old windows" laptops to usable devices again now everything went to the cloud. My computers, my non-techie wife, my 80 year old parents, my 10 year old daughter all took fast to the windows-like look and feel. I use it as a server, master backup with a RAID, and run scripts to the day is long. My LTS 18.04 was installed, what, 5 years ago, and haven't had a single problem or slowdown or virus at all. Before that, I had 12.04 running for 7 years with the same performance.

It just runs, and doesn't get slow as long as you lock out "su" so they can't mess something up