I was going to upgrade my bike (Decathlon Triban 100) and ordered the whole new groupset (Shimano SORA). It will be delivered soon, so my question is how hard is the replacing process? It is not a problem to pay in local bike service for the replacement but I'm also interested in trying by myself. I have a repairment kit and all the things, I like to make some maintenance of bike by mysleft but I didn't do so complex maintenance before.