So I have now finished my Cat, it works and I thought I would document the parts that I had some struggle with, maybe it will help some other new builder. I have build experience from the RC universe, not heavy into to it but somewhat, also have done some work with electronics/software, but nevertheless I got stuck at some points. I will structure it from start to finish and the issues I had, and fill in this thread over a few days, I will expect that you like me have watch the build doc and watched some videos. --- Assembly of body, 5 servos with long cables, they are for head and the four knee-joints 6 servos with short cables, they are for the four thighs, tail and neck Do attach/mount the battery-holder before start of the assembly of main-body, also the bend/breaker is towards the tail. It can from start be adjusted furthest back towards the tail to get balance, head/front simply outweighs the back. Make sure that when you do bend the metal in that 90deegree angle so that it is very close to the plastic when engaged because the leg servo with cable is very close so it does not obstruct movement. In the build doc "Assembling Instructions for Nybble 3.2.5" you do see a part marked red, that part is towards the tail, straight cut end is towards battery-holder as can be seen in picture. The spine is the other way around, that is lift upward into the slots. Thighs in 3.4, Make sure that you do thread the servo cable from the knee servo before screw the spring/servo arm assembly together, the cable should be pointing out from the body back and front not to intervene with leg movements as can be seen in picture. Be observant to that the "battery-holder/wood piece" and the 2 parts for the aurodino should just be inserted long enough to be able to push in the thighs-servos to look the structure, that is not that long. Head, I could not get enough room for the other side of the servo-arm, I had to remove some wood to make room and not get a strange angle. Make sure that if you do solder in the led onto the "eyes" that it does not stick out to much, it will not fit and you can not get the "ear piece" flat to be able to lock it. I did use some shrink-tube to make sure I did not get any shorts. Link to a good overview how to attach the led, https://github.com/PetoiCamp/OpenCat/blob/master/Resources/Nybble_SolderingUltrasound.pdf More on ultrasound-sensor, Before using the 4 leads with female contacts and put that on, you might want to check the 6v setting using two of the leads onto a free servo-connector to make it easier to measure the voltage without causing a short with instrument probes. They should be to ground and the middle pin of a free servo-outlet on the board, this with all servos attached and powered like when you have entered the trim mode. Also check that the setting for "batt" or "vcc", I guess Nybble is shipped with the plastic servos but in my case it was set to "batt" that is for metal-gear servos. Edit's in this the first post in the thread, 2020-02-04 - creation of post 2020-02-05 - updated with link to detailed info. on how to putting the led onto ultrasound sensor, added the segment "More on ultrasound-sensor", some spelling