r2modman is a mod manager which is integrated with Thunderstore, and supports Outward along with other games.
Thunderstore is a mod database which supports Outward.
If you see the 'radio buttons', make sure to click the radio button titled Version X.X.X:mono (where 'X.X.X' is the highest version number you can see) to update to the correct version. Select the drop down and select default-mono. From there, go to Manage Installation > Configure. In order to use mods, you need to be on a Mono branch of Outward.
