Oamo data pools are currently built on Polygon and require you to switch your wallet to the Polygon network to participate in data pools.

To get started, click on the network dropdown next to your Balance on the web app or next to your account on the extension. There, you will be able to select Polygon and automatically switch to the Polygon Network.

If Polygon does not show up, you can always add a custom network by following the Brave Wallet guide here.