The easiest and fastest is that you send your files with Wetransfer,
click on the button to the right to get there WeTransfer

OBS Read about Claims for printing Before you upload photos

Below is just a sample image how to fill in

I want at least to know:

  1. What paper you want, see here to select Various paper
  2. What size, if you want to keep the aspect ratio, just enter longest side = X mm or shorter side