I dont know what the Affects Version is.

The ps4 is a version 8.50

I have a ps4 and bought Minecraft on CD from Gamestop.
 
My son has been playing Minecraft from the CD for a while and wanted to add the StarWars mash.
I then bought the StarWars mash in the Minecraft store (on the ps4) and added it in Minecraft.
 
Now he would like to switch between playing "normal" minecraft and the Starwars minecraft.
 
How can I switch switch between the original world and Starwars world ?