June 3th: Found the module I am gonna use!
I have found the best module to use. It is BL-M8761BU2 which is based on the Realtek RTL8761BUV.
Then designed the schematic and the PCB
Total time spent: 1.5hr
June 4th: Updated the schematic a bit and designed the bottom plate for the casing
I have changed the antenna model to another one
Also I made the bottom part of the case
Total time spent: 1hr