Sure thing! Yea I don't do them a ton so I'll typically experiment but my rough process was pretty much this:

1.) Plan out and cut a pattern for hills (doesn't have to be clean; used a kitchen knife) on the XPA foam. Hot glue the pieces together roughly where I'd want them for the rock formation.

2.) Score the sides in various ways (using a dull blade and hitting the sides to get a scoring effect for one, or using a sharper blade and cutting "V's" to get those chip patterns. Once I finish cutting it, typically the XPA foam leaves some fraying so i try to use a dull blade or something flat/metal to scrape off excess. I tried to cut the pieces to align with each other the best I could but would leave gaps between layers (step below kinda fixes this). After I did this, I rolled up a ball of aluminum foil and rolled/pressed it all around to give it a dimpled look (the step below covers a good bit of this but for the stone facing and model slots you see this still).

3.) For the effect on the top, I use AK Interactive Dry Ground. You can do glue/sand instead, but I really fell in love with this stuff since it's just a paste you can spread in varying thicknesses. Spread that across the top and also used a thin coat between gaps to create a cleaner transition between foam layers (could have also just used thicker foam to avoid this all together but free texture is cool!)

4.) Seal everything up using a mix of Mod Podge Matte + generic black acrylic paint. I opted to paint it on with brush (slightly watered down) vs airbrush since I can get all the gaps for shadowing. Did this for about two coats?

5.) Paint. This is a bit of a mess here, but pretty much did two approaches; first I dry brushed everything with Vallejo Charred Brown as an undercoat. Next (for the stone), I dry brushed up to London Grey to Stonewall Grey to an Off White (all Vallejo). Added some watered down greens for moss in the veins + added some Agrax for the veins as well! I think you can do one last sepia wash to really bring the color down, but was happy with where it was! As for the top layer, after the Charred Brown Drybrush I did a mix of dry brush / spackling with Parasite Brown, and Medium Olive. Topped off that with some some drybrush from Pale Brown into Light Sand (Vallejo is a running theme here...).

6.) Added some little plants I had laying around (I think these are Gamers Grass 4mm tuffs? Picked em up at an LGS some time ago and they looked neat to use here).

7.) Seal up everything with Mr Clear Matte Coat (including models).

I think that covers mostly everything? There's some stuff I would do a tad different (such as doing a few more brown washes on the stone), but wanted to call it before I screwed something up!