I wanted to contribute by running a node and "seeding", but couldn't figuring out how to do this through the GUI with a VPN. I am making this post to help others and to check I have done this correctly. If this has already been answered somewhere else, let me know and I'll delete this post.
I use the GUI because it is easier for me. I use a VPN because I don't want my ISP knowing I run a Monero node and because I don't want my home IP address shared with the world.
The VPN I use allows "port forwarding", but port 18080 was not available. I found this old post which helped me a lot: https://www.reddit.com/r/Monero/comments/3zm2g0/running_a_monero_node_with_a_vpn/
In the GUI I went to the "Node" tab under Settings and then went to the "Daemon startup flags" box. In the box, I wrote "–p2p-bind-port <port number from vpn>".
I also downloaded the "ban list" (https://gui.xmr.pm/files/block_tor.txt) and added a flag for that.
So my "Daemon startup flags" box reads: "–p2p-bind-port <port number from vpn> –ban-list /locationofbanlist/block.txt"
I checked my VPN and it shows that port forwarding is active. When I type "status" in the GUI log command box (Settings>Log), I now show "12(out) +9(in) connections".
Is this all correct? Is there anything else I need to do? Thank you all!!