Mirrored Tablets not working

Hi, I’m new and I’m having trouble getting the mirrored tablets to work in PoE Act 1. I apply the reflections (currently only one available for the 3x3), but no gate is spawning. What am I doing wrong?

As you're going through the acts, you place tiles into the kalandra map area you're shown until the map is filled with tiles, only then can you open and run it.

When you reach mapping, you do the same tile placing, but then when the kalandra map is full, it turns into an item you then open in the map device.