"I think this works! The water is good. A breeze would be even better but you can't have everything." 

She'll have to filter it to make it drinkable, but still. 

"Is this very far from the inhabited areas? I think... If I carry a lot of rocks and chalk out here today and lay out a kiln with them, late tomorrow I'll be ready for a supply of coal and Chimney. That'll give us quicklime, and I can use it to build more things and maybe you can sell it. Then I can figure out what the Spark thinks about whatever seeds we can buy or find in food."

Handwobble about "very far" - surely Waltana knows how far they walked and how long it was since they last saw a person. Gestures of sizes for "a lot"?

"I don't have a feel about navigating underground and couldn't get back on my own.

-The more the better, honestly. At least a couple hundred pounds?"

...Belmarniss squishes her own bicep skeptically.

"Yeah. I can bodge together a sledge with cloth under tension, I s'pose. Or a travois."

"Rynaeri?" suggests Belmarniss.

"If she wouldn't mind? Or's fine with paying back later?"

Shrug.

"I'm really eager to get to work properly. When I'm building things, everything seems alright even if it's not. So I like the plan to ask her."

Nod nod. Up and out again?

Yep! 

She leaves some of the stuff bulging out of her pockets behind a rock so it's less inconvenient to walk around.

Back and back and back they go until they are home at Belmarniss's family cave. Belmarniss drops Waltana off in her room and goes to find Rynaeri.

She organizes and bundles what Stuff remains here for transport.

Rynaeri appears, amenably enough.

"-Hello. I'm Waltana. I don't know much Drow."

"That's okay, little suskna! I'll pendru e ny delao konvit."

She has an intense look of focus as she tries to decipher the unknown words.

"You- Help carry today? I help you some time?"

"Yes! Niss, tsiua, come dassa o eli."

Belmarniss leads the way to the market so they can load up on chalk and junk rock. When they have too much to carry, Rynaeri casts a spell to create a floating disk and they can load that up.

So many exciting possibilities for cutting into brick-shapes and building with!

She's stronger than she looks and will load the disk and take up a heavy load on top of that.

The disk can carry a lot. They need to go briskly, though, it won't last forever. When they're done shopping Rynaeri herds the girls into positions behind the disk, which follows her, perhaps to deter thieves. Off they go up the passages that lead to the cave Belmarniss found.

Or someone after Rynaeri herself... And it's probably an appearances thing, too. She makes sure her saw-handle-thing is still visible.

It happens they are not interrupted on their way. The disk expires most of the way there and Belmarniss sends Rynaeri back home with a bit more chattered Drow before beginning to make several trips to pour all their swag into the slide-tunnel.

Yay, rocks!

"I stay here. You stay with me? Or come back... Uh... When food?"

"I go get food and bring it back here."