Multi Disc PS1 games on PS2 with OPL?

[ClassicGMR]

So maybe one of you can help me with this. I am not an idiot but for some reason I cannot wrap my head around playing multi disc games on my PS2 with McBoot and OPL. I have been struggling with getting Metal Gear Solid to work for example.

 

Can someone point me at a walkthrough guide that's in plain, "for stupid people" English?

 

I DO have a ton of PS1 games running from USB just fine. They are all single disc games however. I start messing around with DISCS.TXT and everything goes out the window.

Edited August 18, 2020 by ClassicGMR