@andreas, unless you have a very old and outdated version of Manager, it is not possible to record expenses with journal entries, because journal entries (in Manager) do not permit the entry of transactions involving bank or cash accounts. When money comes into or leaves the company, those transactions can only be recorded via Spend Money or Receive Money functions in the
Bank Accounts and
Cash Accounts tabs. Virtually every expense is going to involve payment from one or another, so how are you actually recording things?
If your version permits bank or cash account allocations in journal entries, you should update.