I'm collaborating with someone and I'm not sure how to send him the file so we can both work on it. Thanks

send him yourmapname.map file - located in map_source  / zm

If you send just that file are they able to play it too? I have an alpha build done of my map and want friends to test it at this point but dont want to upload it to the workshop for everyone just yet.

just send the yourmapname folder through skype or email then they have to put that folder into their usermaps folder its simple