Every server has option to set how often can player vote, according this option, the score value of one vote is changing. You can change this option once per 24h
Vote and score reset is always when a new month starts (we have all votes in our database, they are accessible through our API).
We recommend use plugin NuVotifier for receiving the votes. After install there should be folder NuVotifier with basic config.yml where you can find your NuVotifier port and token, probably you need to change port for one of allowed (your gamehosting should let you know what port you can use)
Then configure token and port in server editing at our serverlist. When you try vote for server, you should see it in your server console.