Not quite how to do it, but Wanderer already fixed it up for you
The main thing is getting the info there as only the people with squadrons can do that. Then someone with more experience can fix it if needed, as in this case. For future reference though, here's the proper way to do it:
1) Type the squadron name in the search box and hit "Go".
2) On the page it takes you to, which doesn't exist, there's a line saying "There is no page titled <search term>. You can create this page.". The "create this page" part is a link, so click that.
3) This brings you to an edit window, which is where you make the page for your squadron. Use the "Preview" function get the look right if you're not sure of what you're doing.
4) When it looks right, add the line [[Category:Multiplayer Squadrons]]
at the very end of the page, and a link to your squadron page will automatically show up in the MP squadrons category.
5) Save the page.