Sad? Lonely? Here's the Solution!

Then find people and put them inside the boxes. Keep them there. Like, duh.

Or you could stack a few, paint faces on the top ones and make box-people.
Or you could put stuff in them and nice wrapping paper around them and give them to people.
Or you could get a really really big one and pretend it's a boat or a car or a raft going over the rapids.
Or you could get lots and go to the top of a big grassy (or sandy or snowy) hill and use a box to slide down the hill, and then people would want to join in and you'd have all the spare boxes so they could.

The first line is designed to connect with the audience, because many people are sad and lonely.

The second line is because they want to sell you some boxes.

Homeless?
Move into one of the storage units.

Seen near (former) Compaq headquarters.

what's in the box!?

It's a reference to the point of all advertising, which is: "Bored? Lonely? Why not buy something in a cardboard box?"