This repo lists guides on how to install LNbits on a phoenixd node
You will find two scenarios described
Now you will need to send sats to your lnbits by generating an invoice in a reasonable amount to open an initial channel on the phoenixd underneath.
Be noted that channel openings have minimum amounts (pls check docu of ACINQ for that regularily) and also that it will take up channel-opening fees and a fee reserve for potential force closes.
Happy to merge PRs for easier handling and better documentation