Im dumb i dont know if this is possible. I know how to host a server but not if i can just test it for myself to see if everything works

you just host it locally, but I dont know how

You can! You need to have node hill set up and such.
To test locally open start.js in your node-hill installation and change:
local: false,
to:
local: true,
then save it. Start your server and now MAKE SURE TO OPEN launch_client.bat
Then you'll join your locally hosted game