How do I create a new layer?
+ button on the layers bar https://www.scirra.com/manual/42/layers-bar
That's the manual for Construct 2. This is the Construct 3 forum.
Construct 3 doesn't seem to work the same way as I'm lacking any kind of buttons for creating layers.
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https://www.construct.net/make-games/ma ... layers-bar
You right-click in the layers bar to bring up options for adding layers.