The basic thing is to modulate the filter cutoff using an LFO with a sine wave form.
To do this, in program mode, starting from an init prog.
+ P1 => chose single oscilator
+ P2 => chose a sample for the oscillator, for example 0676 Pulse 40%-Pro5. Adjust the Oct parameter to -1 to lower the sound pitch by one octave
+ P5: OSC1 LFO2 chose a sinewave, maybe it's a good thing to sync it to the tempo so check MIDI/Tempo Sync at the bottom of the screen. Maybe later, you may want to adjust the Base note to match your need...
Another option, which is also intersting, is to use slider 6 to modulate the lfo frequency. If you want to do this, simply unchekc the "midi sync" checkbox. Then in the Frequency Modulation part, assign "SliderMod6[+]" to AMS1 with an intensity of +25.
Now, I assume that you want to adjust the "wobbling" effect using the slider. So we cannot use the LFO directly but we are going to use an AMS mixer for this.
+ P6 OSC1 AMS M1. Chose Mixer Type 1. This allows multiplying two parameters. AMS 1 chose LFO 2, it's our sine wave. AMS B, chose for example SldrMod5[+] for using the slider n°5. Amount A should be 0 and Amount B should be +99.
+ P3-1 Filter 1. Chose a low pass filter. I've chosen a pretty low cutoff frequency :28, you will have to adjust that according to your need. Add a little bit of Resonance : 16.
Now let's do the magic : Switch to the mod tab. In the Filter A/B modulation chose "AMS Mixer 1" for Filter Modulation AMS1. Let's use a +50 intensity.
You may now modulate the "wobbling" effect using slider 5
and its frequency using slider 6 (if you have chosen not to sync the wobbling effect to midi/tempo)
+ P4 : Amp1 EG, let's set the attack time to +14 in order to have a "rounder" sound.
You may now have a basic program with a "wobbling" effect modulated by slider 5...
Nb : in order to make it work, you should ensure that the "real time control" button on the left is on (red light).
Now it's time for you to tweak this sound a little bit, for example by doubling adding another oscillator and detuning it a little bit for richer sound, etc.
Don't forget you will not obtain a very nice sound... this are just some explanation about the wobbling effect.
You may modify a korg M3 preset that fits your need.