TRB holders vote on the validity of the data and if the miner is found to be malicious their stake goes to the party that initiated the dispute, otherwise the dispute fee goes to the miner.
Scroll to the bottom of the page and find the Recent Disputes section
Find the dispute with the Open Status and click on Vote
In the window that opens, you will see Your Voting Power and you will see the options to Support or Challenge
Support: You find the miner to be malicious and they should lose their stake.
Challenge: You find the miner is not malicious and should keep their stake.
Select either option by clicking the button
When you click the button a Metamask transaction window will appear
Confirm the transaction in Metamask and then click the link to View on Etherscan