AppImageLauncher is a great tool to integrate AppImages into your desktop. It creates a folder called Applications in your /home folder and any AppImages you download or try to install will end up moved to that folder. Instead of marking the files as executable just make sure you download the files into the Applications folder and AppImageLauncher will handle everything else.
I recall being confused when I tried to install the AppImageLauncher. There are a ton of different file formats to choose from. The file you should be choosing is
appimagelauncher-lite-2.2.0-travis995-0f91801-x86_64.AppImage located on the AppImageLauncher releases page.
I personally use AppImageHub to get all of my AppImages and have found the selection to be stellar. I have a ton of AppImages and the AppImageLauncher handles everything exceptionally well.