I am no expert and very new on here, but this is my 2p
1) Do it yourself and learn how the watch is held together.
2) Start this on the kitchen table with a t-towel under the watch, or any such thing to catch the tiny tiny collars that probably sit somewhere on the pins. Long carpet or hard floors are a no no for small parts that are about to fall out of your bracelet.
3) I bought a very cheap (<£10 pin pusher, it's a screw in type), get one, make your life easier.
4) When the collars and pins come out - carefully note the direction they came out. The pins can have rounded and flat ends, the collars can be shaped too for a set direction of insert.
5) Be patient and put all the spares into a small plastic bag and back into the watch box, not another safe place.
Good luck