I would like to clean D5 watch and install the system from scratch.

Round Custom Faces
1

I would like to clean D5 watch and install the system from scratch. It is somewhere manual how to do it (step by step)?

2

Depending on what’s your goal, you can

  1. Use the system restore function in the Settings menu, or
  2. Flash the TWRP recovery and make a System Wipe, or
  3. Flash a complete ROM.
    For the points 2 and 3 there is a guide in the Guides section, but both require you to be careful and to do exactly what they say.