Hey guys, I’ve been planning to make a FPS for a few months, considered cryengine sdk, but ultimately went to udk due to the amount of documentation. My plan is to make a short, simple sample level to learn my way around the engine. I had also planned to design my HUD and decide on a few of my weapons and some of the enemies in the first level. My first, biggest question is how do I create a door? Like an old fashioned hinged door. Preferably interactable, for example with the E key. I’d also like to know how hard it would be to do a level system, EXP and maybe stat upgrades and skills, if possible. Thanks guys.
Do you mean UDK (unreal engine 3) or the Unreal Engine 4? -> When you mean UDK, please post your question into the udk forum: https://forums.epicgames/forums/366-UDK 
UDK: ?v=uql9V7S_yZM
UE4: ?v=764a5dkzpZ8
In the UE4 it is super easy to create a EXP/skill/upgrade system -> you can do everything with blueprints
Super easy is a relative term 
It depends on how complex your system is. If you are going to do anything even remotely complex, I highly suggest taking some time to read up on the following topics:
Blueprint Interfaces(not to be confused with User Interfaces)
Delegates
Enums and Switch on Enum.
Structs (And to save you some frustration, if you use “Set member on struct” make sure you hide any unused pins)
Have Fun!!
I’m sorry, I didn’t realize there was a seperate forum. Thanks for the info though