OK, you're going to get a refresher course. Probably the same basic sim stuff that the student drivers get, then some time with an instructor locally and training pad drills. That part will be the basic evaluation of where you're at... of course I'm guessing.
You'll also get some time with a trainer OTR, determined by how well you do. Safety, dispatch and your trainer will determine how long before you get turned loose. This is a guess on my part.
Its mostly to break any bad habits that have crept into your driving during your layoff.