I just met a dog the other day who had a bad ear crop/tape job and ended up losing one ear to infection as a result. If you want it done, get it done right.
My suggestion is to contact your local breed club and get a recommendation for a vet through them. Most vets don't do ear croppings regularly and you really want one who knows what they are doing. Boxer ears are cropped a certain way--more like Doberman or Dane ears than like Dogo or Staffie ears. You need to go to someone who has done alot of Boxer ears.
The vet will explain the necessary aftercare to you and show you how to attend to the taping and dressing.
If the tail wasn't done by 3 days old, then you shouldn't do it. After that point, the nerve pathways are completely formed and the procedure becomes extremely painful for the pup and more like an amputation. In fact, my vet wouldn't even consider docking a dog past that point unless there is some health reason requiring the amputation. If the tail hasn't been done, there is no point in doing the ears.