The different downloadable versions you see each work for a particular hardware architecture (arm64-v8a / x86_64 / armeabi-v7a) for which you need to understand what architecture your device uses and download/install the corresponding version.
However, I think it is better to use a client for f-droid (on https://f-droid.org/ you will find the button to download and install the official client), in this way on the client you will only see the versions compatible with your hardware and also you can get the updates of each app as soon as they will be available in the f-droid’s repository.