It's actually minnowbooster and this is a post that tells you what to do. You choose the number of weeks and the amount and then you get it. The rate for 4 weeks is currently 150 for 4 STEEM. Very quick and helpful. My upvote at 100% went from 1 cent to 6 cents :)
https://steemit.com/minnowbooster/@minnowbooster/minnowbooster-tutorial-4-leasing-delegated-steem-power-with-minnowbooster