How to remotely access a Windows network share?

I have a Windows (10 Pro, if that matters) machine that has a network share. It (the network share) can be accessed over LAN. However, when I am out, I need a way to access the network share over WAN.

I have ports open for FTP and SMB, have created an FTP server, a fixed internal IP allocation, memorized public IP address, so, everything I need to know.

How do I map an network share over WAN? Ideally, a method that works for both Windows and Linux.

For specifics, do I "Add network location" or "Map network drive"? And, when I need to type the public IP and port, please separate with a ':'.

Actually, you can do it, provided you can access your router's management interface and open port 3389 (that's the one RDP uses) while you're at home. Associate said port to the private IP address of the machine where the shared folder is (unless it's a NAS), and voilà.

I concur with the security risks FTP poses, as it's NOT SECURE AT ALL, even over your own LAN, let alone when accessed from the outside.