Welcome to Wanikani (run while you still can)
I can understand why you find level one so stressful, there are a lot of threads like this so it’s not just you. It’s just a matter of getting used to the system which, while overwhelming and confusing for someone new, is just fine (why are you still reading this far? didn’t I tell you to run?). Check this guide out, it’ll make things make a lot more sense. If you don’t feel like reading all that, just read the scheduling part (section 4) since it’s the most important.
Good luck