Port Forwarding to seed torrents. Help needed!

For once, there is someone that is trying to use torrent clients LEGALLY, and my post gets deleted on r/Torrents. I really hope I can find someone here able to help, because I need to give these files to my classmates as soon as possible. I'm really not very savvy in this regard, never played around much with modems and routers and their settings.

​

I'm trying to send some files to my classmates but the torrent does not seed. I called my ISP and they finally gave me permission to access my modem's settings (they've refused multiple other times). It's a DSL modem with Ethernet and Wireless outputs, so I guess it's a modem-router device. Before opening the port, a few of my friends had already connected even if upload/download was not starting. (I could see them in the peers list)

​

I have a dynamic IP and considering I don't have a router, I don't see a reason to make it static. The modem has it's own IP address, no matter what IP it assigns to my PC, right? Anyway, while having DHCP activated, I can't change the IP address for the port I want to forward. The first digits of the IP are already set and I can only change the last digits. Screenshot Here

​

I haven't tried making it static, but I'm concerned about the security issues it might cause. I tried opening a port, but it still shows as "stealth" on GRC. After allegedly opening this port, my friends disappeared from the peers list on qBittorrent.

​

My dynamic IP address is completely different from the modem's static address and all the subsequent addresses that are assigned to smartphones and other wireless devices (which are the same as the modem's except for the last 3 digits). If I open this port on my modem, doesn't it also remain open for my PC, no matter what IP is assigned to it?

​

My qBittorrent settings should be okay, and UPnP is enabled. Why isn't it working? Should I reset the router? Should I change the IP to static? What are the consequences of using the same IP address across 2-3 computers and over 5 smartphones?

​

The modem's settings have lots of options and I don't really know most of them. Static Assigned DHCP Clients,Ethernet based bridging, Network Configuration -> LAN, WAN; Port Triggering, Dynamic DNS, Port Filtering, DMZ and lots of other stuff. Is any of these settings responsible? I'm on IPv4 btw and qBittorrent is allowed on the Windows Firewall rules...

EDIT: I just checked and my PC (ethernet) has a static IP according to the 192.168.0.1 page. The wireless devices have a dynamic one.