Metamask is the most common browser extension that enables interactions with Ethereum and compatible blockchains, like Avalanche's C-Chain.
For the purposes of the below, setting up your Metamask for the first time and creating an account on it is assumed to have been complete for this tutorial, but there are a number of resources out there to assist, including from Metamask themselves.
After you log in to your Metamask account, connect it to the Avalanche network.
Select the Network drop-down -> Select Custom RPC:
Hit Save, and then select the Avalanche network you just specified.
You should see your AVAX balance, if you had previously transferred any into that Metamask address. If not, you can now transfer into that address and have it available to be used on OrcaDAO and across the Avalanche network.