If you want to receive zaps as an ecash to Minibits, just link your minibits wallet address to your public profile in nostr client you are using.
You'll then receive zaps as an ecash to Minibits. You don't need to be online to receive, ecash waits for you on the nostr relays.
You can then time to time withdraw from Minibits to any self-custody lightning wallet by scanning or pasting an invoice / address.