Yes the 1st step of setting up a static ip is usually the step that confuses most people if they do make a mistake. This is in fact the most vital step. Without a static ip the entire process won't work after your ip changes. Once you get the whole process right, you'll never look back & will see the value of the concept for forwarding a port. Port forwarding is very common for online games, video conferencing, etc., except those generally require multiple ports forwarded.

Don't forget to save your settings. Some devices require rebooting them to save the process properly & for them to start using the forwarding. I'm not sure about your brand or model.