Some progress and learnings:

Glued the columns

Marked the spot where the minis will be glued, scratched the cork to help the superglue.

Smoothed the cork with milliput (first time).

Vallejo sand texture in the edges.

Basecoated the ground with diluted Vallejo earth with airbrush to prevent grey spots in case the basing materials fall.

Painted the columns with airbrush using army painter ancient stone (first time).

Minis primed and ready for paint.