What do you want to know exactly? How you use them, what they do?
I can give some small descriptions:
- Tone portamento: Slide to the given note from the last played note. The bigger the value, the faster it slides.
- Vibrato: Well, how should I explain this? if you really don't know what a Vibrato is, look it up on wikipedia. The first number of the effect value is "Speed" and the second is "depth" of the vibrato
- Tremor: Turns the sample "on and off" rapidly. Implementation is somewhat buggy in many trackers. First number is supposed to be the "ontime" in ticks and the second is "offtime", but actually, Impulse Tracker adds 1 tick to both values IIRC.
- Arpeggio: Changes between 2 or 3 notes rapidly. First number is the first note (base note + x in semitones), second number is the second note (if only 2 notes should be alternated, use the same value here)
- Tremolo: The same as Vibrato, but with volume and not frequency. Same usage.
- Glissando Control: Glissando means Portamento actually. This switches between "smooth" (S10 in IT) and "note-wise" (S11) portamento, i.e. portamento jumps between semitones and doesn't go up smoothly.
- Vibrato / Tremolo / Panbrello waveform: Changes the waveform of the mentioned effects. 0 = Sine, 1 = Ramp Down, 2 = Square, 3 = Random
- Panbrello: Same as Vibrato and Tremolo, but changes Panning. Same usage.
I don't know what tracker you use, but ModPlug gives nice descriptions if you double-click an effect. (Be sure to use the latest version, OpenMPT 1.17.02.54, because prior versions Including the "old" Modplug 1.16 miss some effect descriptions).