yea, there are some issues.
1. no instruments set. go download the instrument list
2. no tempo. just put t1-100 and keep setting till it sounds right
3. no volume, either use w1-255 or set v1-255 at each channel
4. some channels appear to end early so add some [r1]100s at the end of the shorter channels.
you can specify instruments anywere in a channel, and as many times as you wish, just make sure you use the valid instruments. and make sure you set a default octave on each channel, i use o3 at the beginning, you see, when a channel ends, the last octave it was set to folloows over to the next channel.
Unless The Song Is Being Played By An Orchestra, You Would Never Need That Many Instruments At Once. Even If It Was Played By An Orchestra, One Instrument Per Channel Is The Limit.
Also, why can't you understand the tutorial? Everyone else, me included, learned that way. I also learned from example. If you're really confused, maybe you should see some of the other songs on this site to see how they're arranged.
-------------------- Edit: My postcount went up by 1!