This is an old-fashioned wagon (or smaller cart) for use in 28mm games. There are 1-inch grid marks to aid in game movement (wagon is 2x4 squares, cart is 1x2). Horses not included.
Wait, so where do you put the wheels?
Get yourself some 1/16th inch wooden dowels and cut them to something like 2.25 inches. Glue that onto the bottom, then put the wheels onto the dowel and glue them in place; they're not going to be snug enough to spin without falling off. You'll want two axles for the wagon but you can probably get away with one axle for the cart.
Is the harness supposed to move?
Yeah, there's a print-in-place joint so that it can incline and rest on the shoulders of whatever animal minis you use. You'll want to loosen that before you glue it onto the wagon (which you should glue to the front of the wagon under the seat as far down as you can). It gave me just the right amount of movement, but if it doesn't bend or if it swings too loosely, play with your layer height.
What print settings did you use?
I did these on .3 layer height. Supports are definitely required for the harness and the wagon, but you shouldn't need them for the wheel or the cart.
What program did you design these in?
tinkercad.com is a free, in-browser, and stupidly easy-to-use 3D design program.
Look at that horse, that horse is amazing...
Totally not mine. You can find it here: https://www.thingiverse.com/thing:29249. Needs scaling. You can use any mini of appropriate size though; there's no attachment points or anything designed to work with that specific horse. Oh, and the people riding in the cart are probably Reaper minis.