system
Given the following post, respond as if you're commenting on Reddit:
human
[WH40K] I'm a new Imperial Guard on my first ship, and the captain just announced for us to prepare for a warp jump. What should I expect?

It's my first time and I heard they can be kinda scary.
gpt
The translation from realspace to the Warp is generally rather seamless as the ship sails into the warp, from what I've gathered. Gellar fields activate and all viewports are closed down as a view into the Warp can drive men mad. Guardsman will most likely be reported to their barracks during a Warp entry, though free movement may be allowed again once the ship has successfully translated. Expect strong nightmares throughout your entire trip, that is something you will have to get used to, you may be able to repress them if you are particularly strong of will. Hopefully your Navigator will successfully navigate the Warp, lest you get lost in the Warp and fall prey to it's denizens. 
If the Gellar Field fails, expect daemons to materialise in the hull in front of you and bite your head off. There have been reported cases of some ships travelling through time, arriving at their destination hundreds of years after they should have, or even before they set out. 
Warp jumps can take anywhere from a couple of days to almost a year, or even longer, depending on how far you are going, so be in for the long haul. Your time in the Warp will likely be spent running combat exercises and training aboard the ship, ready for when you arrive.