Re: How do you upload a Custom Map?
Via In-Game, I haven't seen any specific button to do it.
That's why I said what I suggested.
On previous titles (CnC3TW / RA3 / CnC4TT) are anything to go on, then you may need to host a Lobby with your Custom Map, then as people join your Lobby, the map would be transferred (Transfer hadn't used to happen until the match was launched). So maybe try that if you don't want to use External Sites. Please note, this may not work on this Version of the Game, that's why I didn't suggest it before.
