For leverage, take the highest your broker offers. If they offer 400:1 take that. You won't be using that much leverage; you only want it that high to reduce your margin requirements. The leverage your broker gives you has nothing to do with the leverage you trade at. The leverage you trade at is your position size divided by your account size. As an absolute beginner, keep it at 1:1 or less when you first start out, then gradually increase it over time to no more than 5:1. This is all the leverage you need.
As a beginner, your objective at this time is NOT to make money. Your objective is to learn to trade. To do that you have to stay in the game by preserving your capital. Low leverage trades will allow you to do that.
So, start with a demo account and when your system proves itself to you and you feel "ready" to trade for real, i would suggest a trading with very small or micro lots (REAL MONEY !) considerably under your normal money management risk. This will expose your weaknesses in trading real money and help you overcome them and still stay in the game. It is kinda like a "demo" of your trading psychology, how you react with your system....and you won't lose your whole stake, and will learn a whole lot. Size increases with demonstrated confidence.