I have I tunes loaded on my Surface and I have authorized this device. How do I get my music to load on this device?

Same way you get anything else to the device.

Copy it to the device.

this is all new to me chris

File > Add to fiel/folder to library and select what you want added to iTunes.

Adding music and other content to iTunes

Copy it from the old computer to the new computer.

Installing iTunes has never caused media to magically appear on a computer.