This is a draft answer (incomplete).

To get set up on Signet ie sync the Signet chain and claim some Signet Bitcoin, follow [these instructions][1]. (You can run a Signet node in parallel with your mainnet node, ie same hardware)

You now have funds at a non-P2TR (i.e. SegWit v0, bech32) Signet address. Now you need to generate a P2TR address to send funds to so you have funds at a P2TR address (so you can spend from it).

You can't generate a P2TR (SegWit v1, bech32m) address in the wallet using `getnewaddress`:

    ./bitcoin-cli -signet -rpcwallet=insert_wallet_name getnewaddress "" "bech32m"

returns

    error code: -8 error message: Legacy wallets cannot provide bech32m addresses

So you need to construct a Taproot descriptor manually and then import it into your descriptor wallet.

An [example][2] Taproot descriptor is:

    tr(c6047f9441ed7d6d3045406e95c07cd85c778e4b8cef3ca7abac09b95c709ee5,{pk(fff97bd5755eeea420453a14355235d382f6472f8568a18b2f057a1460297556),pk(e493dbf1c10d80f3581e4904930b1404cc6c13900ee0758474fa94abe8c4cd13)}) 

which describes a P2TR output with the c6... x-only pubkey as internal key and two script paths.

If you only want to do a key path spend you only need the equivalent of:

    tr(c6047f9441ed7d6d3045406e95c07cd85c778e4b8cef3ca7abac09b95c709ee5)

To do: Generating a private key, importing the private key to the descriptor wallet, calculating the x-only pubkey, spend from the Taproot descriptor to a SegWit v0 address (sendtoaddress, send back to initial SegWit v0 address)

TBC


  [1]: https://bitcoin.stackexchange.com/questions/98553/how-do-i-get-set-up-on-signet
  [2]: https://github.com/bitcoin/bitcoin/blob/master/doc/descriptors.md