What ever jet your going to be flying, make sure you just take your time during the training.
A few years back I did there initial Lear 25 program, I came out of a Beech 18 straight into the sim without ever flying the airplane first.
After the first day it gets going pretty quick. Make sure when your out being vectored for approached, running checklist, securing engines or whatever it is your doing, that your not doing 220kts while being vectored, its real easy to let the speed get away from you.
Slowing it down is the key to having a good time in the sim or having a bad time. 180kts with a notch a flaps out will give you plenty of time or slower if you can.
If your not ready for the approach, you have your sim partner tell app. control (instructor) that you need a box pattern or vectors to get set up for the approach. You dont want to be just finishing up with checklist right when you are intercepting a localizer.
As the week of sim progresses you get a good feel for everything.
As far as the first week in the classroom, Its fast paced as well, you need to keep up becuase the next day, the ball just keeps on rolling.
The key is, study, study, study.
Before you get into the sim, you want to know all the boxed items by heart, V-speeds, cockpit flows. It will make it alot easier for you when you get hit with that first V1 cut.
Have fun.