Cicca,

Here is a quick rundown - hopefully it makes it a bit more clear.

1. Get upvotes from Minnowbooster by sending SBD to MB. You send a small amount of SBD to the site, and they in turn upvote your content. Good way to get your content promoted.
2. Sell your upvote to Minnowbooster. You do this after joining and go into "Edit Info". Here you can choose when MB can use your voting power, by selecting a sliding scale. For instance, set it to 80%, and MB will only upvote other users content, whenever your VP is above this. You will then get part of that users profit back, for the vote. Simple and easy way to earn money.
3. Lease Steem Power from the market. Simple - you place a lease on MB to lease some SP from people selling. You decide how much you need and what you want to pay for it. It will boost your account and make your votes more valuable. You are going to have to pay about 30-40% APR to the person who leases it to you.
4. Fill lease requests. The opposite. You fill other people's lease requests and make a healthy return on your investment.

I would suggest that you focus on these. For any further clarification, see this post:
https://steemit.com/minnowbooster/@minnowbooster/6rt2mn-introducing-minnowbooster-beta