DIY electrolysis carries risk of permanent scarring if done improperly. If something goes wrong, only you are responsible.
If you would like a single, pre-assembled unit with the foot pedal, stylus and pads included I now sell these on my store: https://shop.imzoe.me/products/portable-galvanic-electrolysis-hair-removal-device
This is based on n3tcat's original design but redesigned around the STM32 to cut down the BOM and make the board single sided. Unlike v3.4, this board requires no soldering to assemble, just a 340mAh LiPo battery and a display which can just be plugged in. It is even cheaper and even easier to assemble at approximately £15/$20 per board!
You should really read the guide on how to order, assemble and use: https://imzoe.me/projects/electrolysis/electrolysis