@heyman526 Hey mate, if you’re asking about arbitrage betting (where you back a horse at higher odds than you lay at), we would suggest to avoid this method with bookmakers that you aren’t promotional banned with.
We would suggest as a beginner, that you stick to backing & laying horse racing promotions. Back & lay one of the favourites in the race, it can be a horse you think will place 2nd or 3rd, or just the best available match on Betfair (back odds closest to the lay odds). If you’re backing with a $50 stake, a lay stake of around $40-$45 is ideal, depending on the Betfair match and how you want to play it. You won’t profit every single race from this method, but you will end up positive overall.
More info can be found on our Elites forums and course we’re we teach more advanced methods and cover Betfair too.