It's really quite simple once you get used to the different parameters.
The real complexity starts when you start messing around with the algorithms. You can get quite different sounds from the same set of 6 operators.
This parameter card shipped with your Volca:
Notice that the parameter list has two groups:
Yellow - those settings that effect the operators.
Blue - those settings that effect everything.
It looks complicated, but I'll break it down.
The LED display will show
1. the number of operators
2. Parameter
3. Parameter value
Here is how you adjust the values:
Envelopes: Rates & levels
It's important to understand that envelopes in FM are different to the standard ADSR envelopes
you might be used to.
FM envelopes are much more complex as they control both rates and levels.
The table on the left shows 8 settings or Parameters:
EGr 1 to EGr4
EGL 1 to EGL4
EGr = Envelope Generator rate
EGL = Envelope Generator level.
So to make your first program/preset
1. pick the # of oscillators
2. Pick the type of EG
3. Pick the parameter value (0-99)
To the left is a pic from the old DX7.Its exactly the same diagram that KORG supplied with its parameter card.
On the DX7 there are seven envelope generators, one for each of the sine waves and a
seventh for pitch.
Both levels and rates can be set anywhere between 00 and 99 for each of these.
For the levels, 00 is low and 99 is high, while for the rates, 00 is slow and 99 is fast, just like on a car's speedometer
Level Scaling
This refers to the situation that occurs with a lot of old string & acoustic instruments.
The original FM inventors were trying to emulate the natural world.
When you pluck a string (in the middle of a violin for example), it vibrates and sustains for a while.
But if you pluck it higher up where it won't vibrate as much, it sustains for less time.
This happens in pianos, guitars, etc.
The pic below is from the top of my old DX7. It baffled me in the old days
It's identical to the diagram on the Korg FM parameter card.
Basically this means that your higher notes won't last as long as your lower notes.
There are 5 basic level/scale parameters.
1. LS BP - Break Point (in the middle)
2. LS Ld - Left Depth
3.LS Rd - Right Depth
4. LS LC - Left Curve
5. LS RC - Right Curve.
The Break Point is impt.
Sounds above the BP will sustain shorter
Sounds below the BP will sustain longer
Right/Left Depth sets the amt above & below the breakpoint
Right/Left Curve sets the degree (linear+/- vs exponential+/-) of how the sounds get longer or shorter.
The depth of each curve varies between a 0 to 99 range.
A zero setting results in a flat (no variation) curve.
A 99 setting produces a maximum scaling depth.
The curves can also vary in terms of shape: +/- Linear vs +/- Exp.
Oscillator Rate Scale OrS
In this setting, the Decay of the envelope/s are effected.
I think it takes away the release ??
The Decay of the EG for each operator can be set ... either for a long (bass) decay or
a short (treble) decay (as in an acoustic stringed instrument).
The RATE can be set from 0 to 7.
The higher the rate, the shorter the decay.
Amp Mod Sense AMS
This adjusts the sensitivity (or depth) of amplitude modulation.
For example, on the Volca FM, this setting will determine how
much the LFO will affect this operator’s amplitude.
The sensitivity to amplitude modulation is variable from 0 to 3 but this
parameter must be greater than 0 before any amplitude modulation will work.
You can set the AMS independently for each operator.
This will create different effects to a modulator operator vs a carrier.
When AMS is applied to a Modulator it creates "wow" effects
When AMS is applied to a carrier it results in tremolo effects.
Key Velocity Sense KVS
This effects how sensitive the keys will be when played.
In other words, it affects the velocity of the keyboard ...
and how that effects the sound.... the amplitude of the operator.
The Range is 0 to 7. Use the velocity slider to change the setting.
A 0 setting = no touch response.
Output Level OLVL
This controls the overall EG level.
Remember that on a FM synths, envelopes control loudness as well as rate,
It's a bit like how the EG depth on a AMP module controls volume in conventional synthesizers.
Range is 00-99.
Note that in some circumstances you will still hear sound even if the operator's output
level is set to "0". (Eg if you have a large DEPTH value for Level Scale depth).
The next 4 settings (OSCM, FrEC, FrEF, dEtu) are interrelated
Oscillator Mode OSCM
Just 2 settings
00 = Frequency Ratio mode = the operator pitch is scaled to the keyboard.
01 = Frequency Fixed = Hz mode - a fixed frequency is produced no matter what key is pressed
Frequency Coarse & Fine FrEC & FrEF
This controls the frequency of the operators in the two Oscillator mode settings.
Basically, you set the main frequency with your coarse control, then fine tune it with the fine control.
If in 00 = Frequency Ratio mode, the pitch will change with frequency.
The relationship is a ratio.
Eg: If the frequency is increased by 2 times, the pitch will increase by one octave.
If in 01 = Fixed frequency = Hz mode,
The setting will control the frequency of the Operators
Detune
The operator frequencies can be detuned over a -7 to +7 range.
This allows you to do very fine detuning.
The initial operator frequencies are set by the FREQUENCY COARSE
and you follow this up with the FREQUENCY FINE controls
part 2 is here:
Links:
----------------------------FM Index--------------------------- 
This creates a delay between the time you press a key and the start of LFO modulation. 
(00=off, 01=on)
This selects the waveform output by the LFO. 
Range: 00-07
Range : 00-48
