How do I transfer THETA to Metamask?

Could you please elaborate on the process of transferring THETA tokens to Metamask? I'm a bit unfamiliar with the specifics and would appreciate a step-by-step guide. For instance, do I need to have a Metamask wallet set up beforehand? And once I've initiated the transfer, how long does it typically take for the funds to reflect in my Metamask account? Additionally, are there any fees associated with the transfer, and if so, how are they calculated? I'd like to ensure I'm fully informed before making this transaction. Thank you for your assistance.