Where to start with fresh install

Ok Reddit AV people, help a dad out, I haven’t done this in a long time. I have a 2008 Cadillac srx, I found a used Kenwood dmx 1037S on the swap and buy for a great price coming out of a car that was sold and this unit removed from. I chatted with crutchfield and they sent me everything they said I would need to do the install. I have found the manuals online for both the Kenwood and the PAC and bookmarked them. So where do I go from here? If you were going to do this build yourself what’s the steps you would take? Any and all help appreciated! Thanks in advance!