Go to the vote webpage https://www.mc-bananacraft.net/index.php?route=/vote/ or use the command /vote in game to be able to vote.
To receive the maximum amount of rewards per day you will have to vote on all 7 sites.

Survival

Per vote= $100 + 1 voting key
Total per day = $700 + 7 voting keys + 1 Rare key

Teleport to the /warp crate to redeem your keys to get additional rewards!
For redeeming 7 keys you will get an Rare key!

Skyblock

Per vote = $100 + 1 voting key
Total per day = $700 + 7 voting keys + 1 Rare key

Teleport to the /warp Crate to redeem your keys to get additional rewards.
For redeeming 7 keys you will get an Rare key!
Vote for a week and receive the legendary key!

Lobby

Per vote = 1 mystery box
Total per day = 7 mystery boxes