Summary
I had merged two things for my use.
Adjustable tablet holder for DJI Mavic PRO by smsagenthttps://www.thingiverse.com/thing:2020007
Tablet holder for cross trainer by MS_Engineeringhttps://www.thingiverse.com/thing:2233506
Requirements
M3x25 Screws and Screw-nuts x 2 set
M3x18 Screws x 4pcs
M4x12mm HEX-head screw and Screw-nut x 1 set
You might need to make holes a little bit bigger to assemble.