The following video explains how to use your Trezor hardware wallet with MetaMask, including how to set up and access accounts, how to access standard wallets and passphrase-protected hidden wallets, and also covers how various accounts differ from one another:
Information on how to connect Trezor with MetaMask can be found in this article.
If you have trouble connecting your Trezor with MetaMask, please make sure your configuration meets the following criteria:
If you can't see the desired address with your funds in "Select an account" while connecting Trezor to MetaMask, it means you are accessing a different wallet. Either you have a different recovery seed stored in your Trezor or you are entering a different passphrase.
To access the wallet that includes the address you want to add to MetaMask, you need to use the same combination of recovery seed and passphrase you used when you generated this address for the first time.
You can find more information on issues with passphrase in this article.
This issue is most commonly caused by the old version of MetaMask extension. There may also be other reasons, so please make sure that your configuration meets the following criteria:
If the MetaMask app is preventing you from spending your funds (signing a transaction), this might be caused when the (appropriate) private key is missing. Private keys for signing transactions are derived from the combination of the recovery seed stored on the Trezor device and passphrase (if enabled and used). Hence, if a different recovery seed and/or a different passphrase is used then the private key differs and therefore cannot be used. In such a case, previously generated wallets/accounts in third-party apps would become watch-only wallets without the possibility of spending the funds.
To be able to successfully sign a transaction, you need to use the right combination of recovery seed and passphrase for the address from which the transaction is being made.