Disney Transport does not run on a set schedule.
From Poly, you will be taking the monorail to and from MK & Epcot. The monorail to the MK runs frequently; I think it's about every 5 minutes. There is also a small boat that circles among Poly, GF, and MK.
To get to Epcot, you'll take the monorail around to the TTC, which is about a 15 minute ride, or walk to the TTC, which can be as short as 5 minutes depending on your room location. Then you'll board the Epcot monorail at TTC, which I think runs about every 15 minutes.
To get to DHS, AK, or DTD, you'll take a bus. The buses run every 20 minutes or less, but they are not at a fixed time. Occasionally, you might have to wait longer.