I don't know how to upload multi channel BRSTMs onto Brawl Custom Music. Can someone please help me with this? TheUltimateKoopa, Segtendo and all of those guys can do it just fine and I want to know how as well.

For example, the Overworld theme from New Super Mario Bros. 2 has the gold ring variant and the leaf beat included in the BCSTM. I only want to upload the gold ring variant and I don't know how. Please help!