1. Buy a cheap Dell Optiplex or some other hardware on the “known good hardware master list”

https://community.start9.com/t/known-good-hardware-master-list-hardware-capable-of-running-startos/66

2. Flash StartOS from nostr:npub126ntw5mnermmj0znhjhgdk8lh2af72sm8qfzq48umdlnhaj9kuns3le9ll on your new hardware

https://docs.start9.com/0.3.5.x/flashing-guides/os-x86

https://github.com/Start9Labs/start-os

3. Install Bitcoin Core, electrs and a self hosted mempool (and other desired services) in StartOS from nostr:npub126ntw5mnermmj0znhjhgdk8lh2af72sm8qfzq48umdlnhaj9kuns3le9ll