Literal translation of “wall in” should be “emmurer”, which literally means “put someone/something in between 4 walls”

However, usage for this word has often to do with a state of mind, like “s’emmurer dans le silence” -> “refuse to reveal any information even if it causes complications and can’t help”

Correct way of saying “build a wall here” is “construisez un mur ici” or “édifiez un mur ici” (last one is more formal). But playing a STR, I and most of my friends would just say “wall là”, franglish.

The literal translation exists and is murer.

However, it is nowadays almost only used in specialized expressions like murer la porte or murer la fenêtre.

If you want a single verb, an alternative might be cloisonner (build a partition).