Have you got a firewall on the PC? I know that is a rhetorical question, but still...
You (might) need to open a port on your software firewall on the PC, via a new rule. Read the documentation of the firewall you use (you do use a firewall on the PC, right?), and it should explain how to open a port from a remote IP-address (your camera) doing FTP into your PC.
Safe setting is that you only open the port for that camera... You never know.
By default your FTP software has a 'base' address where stuff is put to if you do not specify a path, and you could put it in a sub-folder, but for initial testing leave the folder-part empty, and it would go in the 'root' area of the FTP service, as it is configured inside that FTP (Filezilla). Baby-steps...
And passive vs active ftp is the way the connection is set up. Normally for your setup use passive, which means the camera initiates connection and control... At least that is how I always understood it.
But for comparison you could Google it, there must be gazillions of sites explaining it better than I would.