Packaging for windows store (appx)

i wanted to package my game and make it uploadable to windows store
from what ive been told from Microsoft it needs to be in an .appx format.
please can you instruct on how to achieve this please.
ive been on the web for 2 days now and i cannot find a solution to this.
also my splash screen inst working when i start my completed 64 bit packaged game.
i have set the pictures in the project settings, i have used png images.
thank you for your help.
i appreciate your time.

Hello ! have you find a solution ? i’m in a similar situation and cant find anything on the web about this appx and UE.