People don't generally ask for gold unless it's some joke amount like 69 or 420, although if you do well the commander will sometimes pay you after the battle.
If you want to fight you'll need to make sure that you're in the right teamspeak channel in time for roll-call, which is usually 20-30 minutes before the battle. Teamspeak info should be listed under the "Briefing" tab or in the little message icon next to the commander's names. If you don't show up in time for roll-call you'll be considered absent and removed from the roster to make room for someone else. This goes both ways; if you didn't get accepted ahead of time, you can sometimes go into teamspeak before the battle and take the place of someone who got removed.
When you get into the battle make sure to listen to the commander's instructions. Strat battles are a team effort and if you don't work with your team you may not get accepted next time. If you're dying a lot and not getting any kills consider hanging back and guarding your team's spawn or forward base instead. It's not as exciting as being on the front lines, but it's an important job and you'll get the same amount of experience either way.
Each player has a Reliability rating and a Performance rating that you can view by checking out their profile (click their name on the roster). These ratings only draw from your last 10 battles so you can improve them over time. Reliability is based on how many times you miss a battle. If you show up for every battle that you're signed up for your Reliability rating will be 10/10, so only apply for battles that you'll probably be able to make and retract/cancel application if you're going to miss it. Performance is based on your kill:death ratio in strat battles. You'll probably go negative in your first few battles, but commanders also have older players who'll go positive and make up for it so they're usually pretty forgiving, especially if you're listening to instructions and doing your best. Like I mentioned above you can also contribute in other ways by doing things like guarding your spawn, forward base, high-scoring archers, etc.
