This model is probably not suitable as a toy. It is a display piece. It will not withstand rough handling.
I did not include detailed assembly instructions. I did include several photos that you can study for assembly. The only tricky part is the front wheel axle assembly. The wheels rotate to allow a turn. The tongue also pivots up to allow the shoulder harness to go over the horses.
I did not add a white tarp to the wagon but it should be fairly to cut and apply white fabric to cover the wagon.