Load an instance of a synth, select a patch, load another instance of the synth and select a patch, load another instance of the synth and load a patch, load another instance of the synth and select a patch or......
Load a single instance of the synth with the layers baked in ?
For me I like complex sounds since I got bored with simple synths long ago so layering is one of my favorite things. I used to accomplish it by triggering several hardware synths at the same time through midi but on the same channel.
Now I can do it within a single synth.
I'll still layer synths in my DAW but I much more often layer different synths rather than the same one, layer two or more complex patches and revel in the glorious sounds.....