You must read any tracking tutorials, even if you has no sense. You read first time, and get very small sense, you read second time, and understand some more. Then you must try things by yourself, practice is only real way to learn tracking.
TFM MM is not best tracker to start from, because it's specific. 'AR DR SR' stuffs not related to tracking, it's related only to YM2612 (sound chip synthezer which used in SMD). It's parameters of syntesis, very programmer- or hardware designer- stuff. You can try to read YM2612
documentation or some articles about FM synth basics (like
this one, first which I found now), to make sense.
I think, in your case better to start with pre-made instruments (which comes with tracker), you can learn about FM synthesis after you learn tracker basics.
Go to into 'Instruments' tab, click 'Open instrument' button (in right part of window, with open folder icon). Select file from 'instruments' folder. Try this instrument in action by screen keyboard. Learn about 'note' keys - it's letter keys which mapped to notes. Z=C, S=C#, X=D, etc. It's like piano keys on your computer keyboard. Next, go to 'Patterns' tab, it's where you write composition itself. Pattern window consist six channels (vertical columns divided by vertical line), each channel contatin 64 note fields by default (it's pattern length, which can be changed). Each note field in pattern contains 4 values:
--- -- -- ---
First value is note. You can enter note here (by note keys) which current octave; you can change current octave by Numpad number keys.
Second value is volume of note, in hex. 1F means maximum, 01 means minimum, no value means that prev. value will be used (1F by default).
Third value is instrument number. If you loaded instrument in slot 1 (in 'Instruments' tab, list at right of the window), enter 01. Or enter nothing, and last assigned instrument will be used (01 by default).
Last value is effect field. Here you can assign some effects for current note, like vibrato, slide up or down, etc. Learn about this value later, it's not very basic stuff.
Now try this. Load instrument 'kick' (any of). It will sounds like bass drum if used in low octaves. Go to pattern window, and enter note C-2 on each fourth line (press 2 on Numpad to select octave 2, then enter notes by Z key). You get something like this, in first channel:
C-2 -- -- ---
--- -- -- ---
--- -- -- ---
--- -- -- ---
C-2 -- -- ---
--- -- -- ---
--- -- -- ---
--- -- -- ---
... repeating to the end of pattern - note line, then three empty lines, and again, and again. Now change speed of playing, because it's too fast by default - enter 6 in both 'Speed' fields. Press 'Play' button (F5), and you hear simple straight beat.
Now you can experiment with this straight beat by adding notes between entered ones, making simple drum bridges. Then you can load second instrument, snare drum for example, and enter it on second channel (don't forget about instrument number in note field), etc. You get how all this works if you will practice and experiment.
Sorry for short and unclear explaination, it's difficult for me to speak about so complex things in english.
