Steam to xbox?

I cant get a straight answer, can someone please answer me? i dont want to make a mistake with my accounts.

i play on steam, have the account with PoE1 and i have early access on PoE2. i would like to play this account on my xbox.

do i take the steam access key and put it on my xbox? does that give me access to this account? then just buy early access? i apparenty have PoE1 account on the xbox from years ago. but dont need that connected to PoE2. so do i just take my key to xbox and it gives me access to my steam account as default for the PoE2 on xbox and cross progression?

or do i have to do something with that old PoE1 accound on xbox to play PoE2?

I am so confused. why couldnt they explain this more clearly.