DESIGN BOARD OUTLINE

[rattan]

Hello, I am learning Altium and as a hobbyist i want to implement my design with nodemcu on PCB. I am using Grove Accelerometer board with nodemcu and The board does not have a footprint and i have to create it. So regarding this i have few queries.

1. I want to create an outline on the main pcb for Accelerometer board and a four pin male header for connection. How can i do it and which layers i can use to create it?

2.As the accelerometer board have mounting holes, so i want to use those non-conductive mounting holes to screw the accelerometer to main PCB board. for that how i can define and design the mounting hole on the main pcb.?

Thank you 

[thm_w]

The best way is to make a library component for the module.

Make a new part, draw your headers there, put a silkscreen boundary around it maybe with some description, and add mounting holes.
For physical shape, layer can be M1 or whatever mechanical layer you've standardized in your library for component outlines + 3D bodies.

You'd then compile the library, add to your schematic, and then place on the PCB.