I strongly recommend all of you to book 1 or 2 hours in a 737 simulator prior to take your phase 4...
I failed at this stage, 3 months ago and (fortunately) have been invited to re-sit within 6 months..
This was, on my point of view, the hardest part of the selection process as you're not simply asked to turn right and left...
During the briefing, the instructor will explain you the fundamental first, then will talk about the link between speed and attitude...He will give you 3 speeds (250, 210 and 170 but I'm not sure) and 3 correspondant pitch..
Once in the simulator, you'll have, when requested, to maintain one of these speed by adapting the correct pitch...As you may know (I didn't) to keep a speed, you apply 56% of N1 prior to apply your pitch...You will have to put 56% power by the way...
The only question I was asked were the current altitude, our vertical speed, our heading...
So, use the trim ALL THE TIME, you are flying a 50 tonnes aircraft and it's really realistic...Concentrate on your pitch ALL THE TIME not on the vertical speed indicator..
But do not think guys that it's an easy stage...Download the 737-300 panel for your Flight simulator to familiarise with the instrumentation, then if you have 500 pounds, by one hour with an instructor, you won't waste your money..
When finished, make a positif debrief, do not hesit to tell :"I think this was well done but I should improve that.."...That's what saved me..
Hope it helped, forgive my approximative english.
The best for you guys, Try to sleep the night before, be involved during the briefing and remember 2 words...TRIM and PITCH
See you in NZ.