I will try to answer your question here one by one and clear some things as to how SteemMonsters works. XD
First things first, NO! You do not receive any Steem/SBD or even get your opponents cards from winning battles against them. The only thing that happens when you win a match is that it only increases your Battle Rating (and decreases when you lose a match) nothing more nothing less!
The rewards also are deeply tied to your Battle Rating. Every Season, SM players are given some time to reach the highest battle rating they can achieve which usually
last for 2 weeks (14 days). At the end of the season, depending on your Battle Rating League, you will get some number of Booster Packs. The highest league at the moment is Champion I which is around 4700+ rating which gives you 30 Booster packs!
They also have Daily Quests in which you are tasked to form a team based on one elemental deck. Usually you are tasked to win at least 5 matches with a corresponding summoner element. Complete the task and earn yourself 1 Booster Pack, daily!
But that's not all SteemMonster has to offer. A lot of people don't know this but they have a Discord Bot that upvotes blog posts with the #steemmonster tag. All you have to do is go to their server and use the command:
So while they might not give liquid Steem/SBD (at the moment), one could still take advantage and be rewarded for sharing their experience on Steemmonster in a blog-post style. Or you could try joining their Art Contests/ Voice Acting Jobs and Story Telling contests, that could also net you some liquid SBD/Steem. XD
Neither. Every 24hours you have a task you must accomplish in other to claim a free booster pack. What you gain for winning your matches are points, which as they accumulate your ranking goes up and you qualify to be in certain league. There is several. We have bronze league, which I'm currently in, silver, gold, platinum and champion's league. Each league has three tiers. Depending on how many points you finish with at the end of the season you're entitled to a number of booster cards for their tier. So for example. The first tier of the bronze league entitles you to two booster cards which you get at the end of the season.
So i hope this information is useful to you.
Well the things does not really runs that way.
While to start you will have to buy a starter pack I assume you have done that, after that you will play accordingly. There are 2 ways two play Steemmonster as of the moment
1) Practice game: this is where you can play but you will not be rewarded or your rank will not improve
2) Ranked Game : This is where you can play and earn Booster packs in return (If you get to go in a certain level) After winning you will be awarded with rank/points and at every game you win you will approach to next league and at the end of the season you will be awarded with Booster packs. (Those booster packs can be sold in Steemmonster market/in their discord server )
While in case of another way you can register for upvotes from Steem monster and in every 24 hour period if you upload a post related to Steemmonster they will upvote your post (so in a way you are getting liquid Steem/SBD as well)
Hope it helps.