Basics
Your account is a company account: you prepare statements for your own entity, so there is no clients list. An engagement is one period's file holding the trial balance, statements and notes.
Creating the engagement uses one engagement credit; the wizard shows your available credits before you create it.
Check that your entity's name is written exactly as on the commercial register — it is what prints on the cover.
For the next period use “New engagement → Roll-forward” in the engagements list to carry the chart, mappings and settings over, then upload only the new trial balance.