Other OS meaning windows cannot remotely access the TC without very careful setup.
See the info supplied with filebrowser.
http://www.stratospherix.com/support/gsw_timecapsule.php?page=6remote
You will not find it easy and it is always a security risk opening SMB to the outside world even if you port translate.
The correct methods are here.
AirPort Disk - Remote Access (3 Methods)
Unfortunately from a PC none of them are suitable. BTMM is Mac exclusive. And when you use WAN access it only opens AFP. SMB is only available from LAN side.
The only method that works (reliably) manually setting it up, is AFP. The method 3 from Tesserax.
AFP is not available on PC so that is not going to work unless you have a Mac.
As you can see Apple designed their router for Apple exclusive use over WAN. Filebrowser method is, as they warn, not working very well due to changes Apple made. And the fact that ISP generally block SMB opening.
The only secure and reliable method of access is to buy a VPN router and make it the main network router. These are not expensive and I strongly recommend using OpenVPN over something like IPSEC which gets extremely complicated.