I have an XZ2 Compact and I've sussed out how to change it on my phone - hopefully yours should be a similar method:
Select "settings"
Select "appearance"
Select "shortcuts"
This will (hopefully) take you to your home screen and the other screens where you swipe side to side and there will be some icons (widgets?) underneath.
In the top right hand corner of each screen, you'll see an "X" - DON'T press this, as I assume this will delete that particular page.
However, if you look at the top left hand corner of each page, you'll notice that each page has an icon that looks like a house. If you swipe left and right you'll notice that they're all greyed out apart from one - this is the home page.
To select your home screen, swipe left and right until you reach the desired page and click on the "house icon". This will automatically deselect the current one and select this one instead.
Keep pressing "back" until you exit "settings" and hopefully it'll be back to normal :)