Not sure what you are actually asking
From some experience though...
First, make sure you or someone who is familiar with acclimatization is home to receive. While the places I have used package their fish very well, it is pretty important that the poor things not sit for hours once they arrive before they see the light of day again. Plus, with the temps these days (hopefully things are going to cool off), the cold paks the stores place in the box aren't going to last that long.
Prior to delivery, I would say the day you order the fish, check your water parameters and do a PWC
..about 30% or so unless some parameters are a little off.
There are two ways to acclimate...drip method, which is better for things like corals and inverts, and the ye old "float the bag" method for fish. You can find both methods at LiveAquaria.com under acclimation.
Aquarium lights should remain off and even the room shoud be dim...maybe no lights..just window daylight during the acclimation process and for a few hours afterwards. This is supposed to 1. reduce the stress and 2. get the critters used to light again considering they have been in total dark for anywhere from 12- 24 hours, stuck inside a box that probably resembles a hurricane while they are in transit.
Acclimation Procedure for Aquatic Life: Welcoming Home New Arrivals
The drip method can take a while but it seems to work well. I have used both methods for fish and only the drip method for the inverts. My recommendation for the drip method, however, is to get a hose clamp rather than tying the knots. Makes life a little easier