Altium Layer Standards

Altium doesn’t seem to recommend a standard for layer numbering and use, so below is a usable standard combined from a few sources. Note the layer pairs which need to be specifically designated as pairs in View Configuration in order to properly switch from top to bottom when parts are flipped.

Component Footprint

PCB Layout

Layers follow scheme described above, with below additions:

View Configuration Example

3D Models

It's important to put 3D models on the proper layer, or else they won't move with board thickness changes correctly.  Before physically locating a 3D model, specify both the board side and layer (see below).