O.p. needs to take the bike to a co-op, LBS, or bike mechanic friend. If they had the ... whatever it is, to make those brakes work, they would be working. Videos help people who have the innate ability to make sense of mechanical things. They usually have been able to get into the ballpark without help, but a video can crystalize some of the minutiae. The quality of the pictures taken, the vagueness of the o.p. line of questioning makes it clear that they would not understand written instructions which is all anyone here can provide.

I personally have found that rear discs, especially on tandems, need pre-load to make them work well, or at all. In the o.p. picture, the anchor bolt is fully sunk to the 'rest' position, which is not in itself evidence of no preload but I'm not betting that they know it's necessary. On the picture of the front caliper, the anchor bolt is barely off of the fully actuated position. That wheel should barely turn. Throw in the shop towel and get local hands on help, o.p. That is the way.