These are not difficult but do require some “expert” advice that is not in the instructions to insure that they work and continue to work. Train Buddy published the first one (8-40B) back in 2018. The 8-40B video has updated text and information on installing decoders in general in N scale models. Also shows correct cleaning and lubrication. The SD60 is newly published but completed also back in 2018.
click to go to channel: https://www.youtube.com/channel/UCl4j4n8ziub6blV4PoZyxIw/