I want to use my hardware signer, such as Coldcard or Trezor, with my Bitcoin node. How does this work?
You do not use hardware signers directly with your node. Hardware signers interface with wallets, and wallets interface with nodes. Here is what the stack looks like:
Node (on StartOS) <— Wallet (Sparrow, Specter, Electrum, etc) <— Hardware signer (Coldcard, Trezor, etc)
You use your hardware signer with your wallet, then instruct that wallet to use your Bitcoin node as its node.
Nodes are for interacting with the Bitcoin network: enforcing consensus rules, validating and relaying blocks/transactions, and broadcasting transactions.
Wallets are for constructing and viewing transactions, as well as generating addresses.
Signers are for generating and storing keys, as well as signing transactions.
The reason there is so much confusion about these 3 concepts is that the Bitcoin Core node comes with its own Wallet (which you should not use), and that wallet is also a signer. In fact, most wallets double as signers, and many wallets do NOT support connecting to your own node. So, most wallets are actually serving as a wallet, linked to a third party node, and a signer, which might be convenient, but it is neither trustless nor maximally secure. Ideally, you are using a wallet that supports both integrating with a hardware signer (like Coldcard or Trezor) AND a backend node (like on StartOS).
Can I use my ledger Nano X in this way. Do I have to interface my ledger with a wallet then interface the wallet with my Bitcoin node on my startOS…(If so , I have no idea how to do it)…
Correct. You can set up your node, and optionally an indexer (electrs on StartOS), and then follow our directions to use your wallet of choice. We recommend Sparrow for desktop use with hardware signers. Then follow Sparrow instructions/guides to set that up with your Ledger.