am i doing it right?

Yep it's that easy
Whenever you download an app, generally you drag it into the Applications folder even if there isn't a shortcut to do so. Really, you can have the app wherever you want, but the Applications folder is where Apple wants you to put it.

And for deleting, yep, thats it. Drag the app to the bin and thats all!
Some apps leave a folder in your ~/Library directory but you can ignore those. Theres no need to go and delete them unless your really picky about keeping your Mac as clean as possible. They usually only take up a couple of KB, so taking up space isn't an issue there either.

 

It's funny you're talking about Photoshop. Because photoshop installs it's files everywhere. And it has an uninstaller. You could just throw the folder with photoshop away, but it's better to use the uninstaller. So yes, most programs you can just throw away. But if a program has an installer, changes are big you need an uninstaller to really uninstall it.

 

For the most part, the applications themselves are those application_name.app files. They are essentially folders with the files the app needs to run. Right click an application and select "View package contents" to see the folders and files within. Don't edit those though..

They may create and store files in the system Library folder, or within your own user's library folder (This holds settings and stuff). There may be other areas it could throw stuff, so if it has an uninstaller, use it.

I usually just use a shareware program called appzapper. I open it, drag the application in, and it finds most of those other files. I hit the button and it's all gone.

 

Dragging an app to the trash will uninstall it in most cases. Occasionally, an app will have a component that leaves an icon on the Menu Bar or a process that launches automatically. If the app has an uninstaller, that usually takes care of it. However, even with uninstallers, apps will leave files/folders behind. They usually only take up some drive space and won't affect your performance in any way. If you want to be thorough about eliminating everything associated with a deleted app, the only effective method for complete app removal is manual deletion:

Best way to FULLY DELETE a program​

App removal software like AppZapper, AppCleaner, etc. doesn't do a thorough job of deleting files/folders related to deleted apps. For more information, read this.