Product review (3 stars): Have it installed by a professional
Here's my recommendation.  If you're buying a new dryer, purchase this product with the dryer and have it professionally installed. Especially if it's a model like DLEX4270W.  The instructions that were included were so poorly printed with small print that they were almost unreadable.  They are also for an older or other models which do not have a welded side punch out.  I had to use a hacksaw to remove the side cover instead of easily popping it out as videos and instructions suggest.  Other misleading instructions are inserting the second exhaust vent into the elbow.  The fitting was so tight that it took about 20 minutes to get it together inside the dryer.  One last item is the back cover holes do not align with the dryer so it doesn't fit properly.

Yes, you could dismantle your entire dryer as shown in most videos instructing how install this kit but it's not worth it.  Just order your dryer from Home Depot, include this part and have them install it for free.  Then if you have any issues with it, Home Depot owns the issue not you.