I used F38 in the engine compartment and bought this fuse kit from Amazon. I used a 20A fuse in it.

RCA cables from the subwoofer out on the head unit to wherever you put the sub. It has a 15A fuse so you don't need to go from the battery through the firewall to the amp, like you would for anything much bigger. Are you comfortable reading your fusebox diagram? You might be able to skip the remote turn-on wire if you find the right fuse. Otherwise you'll need like 18ga wire from the head unit, along with the RCA. https://www.amazon.com/Nilight-Circuit-Standard-Profile-Warranty/dp/B08QJHXRN6