You can find course descriptions, along with a self-diagnostic exam and our recommended level, here: https://alphastar.academy/mathematics/.
If you are new to math competitions, we generally recommend starting with the following levels:
After reading the course descriptions and taking the diagnostic exam, if you are still not sure about the right level, we encourage you to schedule a free online consultation. You can also email us at info@alphastar.academy with your student background (grade, exam result, any official/practice contest results, if any), and we will be happy to recommend a level for you.