You are not going to get any help from the manuals on the bushings. Not to be disrespectful but from technical viewput it would be like asking for instructions for installing the ignition key. You just got to do it. Clips at each end of the rod, remove rod and install the bushing in hole. Not exactly easy on some models. Almost impossible if its in a 201, pretty simple in a 126.
As to the tensioner, I am wondering why you are replacing it. I don't think our shop has ever replaced a 103 tensioner. If we did it was not for a failure as I have never seen either chain or tentioner failure on a 103. The main thing to know about the tensioner is that it is a ratcheting style and has to be assembled in the head. If it gets extended before assembly into head the chain will be overtightened upon tightening.
Bosch Master, ASE Master, L1
33 years MB technician