You can totally just install the latest release straight from the git repository. However, how often will you remember to check if there is a new release? If you want your apps to stay up-to-date you have 2 options. (Ordered from least effort to most effort)

1. F-Droid (minimal setup, slower releases)

• Install F-Droid or one of the many 3rd party clients (I like Droid-ify the most right now)
• enable the IzzyOnDroid F-Droid Repoin the Repository settings of the F-Droid client
• install FreeTube Android

2. Obtainium (moderate setup, quickest releases)

• Install the latest release of Obtainium directly from the git repo
• go to app configurations search for Obtainium and click on the add to Obtainium button so that Obtainium can update itself when there is a new release.
• In Obtainium, click on Add App. Then insert the release page URL for FreeTube Android (github.com/MarmadileManteater/…/releases) as the value for App Source URL, then click the Add button next to it and you are set.