I can write a small tutorial for people who are not familiar with it:
1. Step is naturaly, to load the Xlutop Chainer to an FX slot, and assign an instrument to it. After that, open the Chainer and load your VSTi to it (Synth1 for the example).
Then right click to the plugin's secondary editor (as bvanoudtshoorn already described):
So the parameter menu opens and you can scroll trough and modify every Synth1 parameter.
If you right-click to any parameter, you can assign it to Chainer's own MidiCC from 0-127 (after right-click, go Controller and chose your desired "slot", my choice will be "0" for this example):
Okay so far, now lets open the Zxx Macros panel in "Patterns" tab:
Now lets assign our Chainer plugin from FX1 "vst plugin slot" to SF0 "Midi Macro slot" and choose that CC we'd like to automate with SF0 command. (i will choose the CC0, 'cause i've already set that up above):
all right! we're ready, now you can automate the desired Synth1 parameter through Chainer, with Zxx (for instant automations) or with \xx (for nice and smooth slides):
additionally, with Chainer and OMPT you can control 16 (SF0-SFF) different MidiCC-s of a single VST(i), even simultaneity (choose any 16 channels in Patterns tab and use SFx and Zxx or \xx on them as desired), and that is just for one instance (instrument slot) of Chainer. If you need to use a second, totaly different VSTi, or the same but you desire different parameter control setup, you can open a second Chainer plugin to the second instrument slot, load up in it your desired VST(i) and set up your control parameters randomly to Chainer MidiCC (like i demonstrated on the second picture), again up to 16 (0-15) (without modifying the Zxx Macros Configuration), so in the end your Zxx Configuration will look like about this:
One more good thing, you can assign MORE VST(i) parameters to SINGLE Chainer MidiCC slot, so you can automate as many parameters as you like with one SFx and Zxx or \xx command (example i did set three Synth1 parameters to Chainer's MidiCC "7", and i can now control all of them, in my case, with a single SF7 and Zxx or \xx command on a single channel).
The 16 SFx Macro slot "limitation" is not an issue with Chainer anymore, using 16 parameters at a time (or more if you set more VST(i) parameters to a single Chainer MidiCC) of a single VST(i) should be more than enough for every musician, and that's just for one instance, open up another one and set parameters differenty, you will get whole different of settings to control just with a simple instrument change (without modifying the OMPT's Zxx Macro Configuration again).
Hope this helps!