Hello everyone,
We are now on our frame stage and we have observed that on our backyard has a fall so we need a retaining wall. Please see photo 1. If we will level the backyard with our slab it will nearly fill half of the fence and I know this is a dangerous thing with our neighbour at the back.

We have contacted our fencer and he told us we need a retaining wall on side of the fence and it will take up a meter if the space of the backyard. I was anxious since my plan for our backyard is may garden area so I do not want to lose any space. The length of the backyard from the back of the house up to the fence is 3.2m.
So I researched on how to avoid wastege of space and I found the following:

I just don’t know how to apply these on our backyard since our space is too narrow.
Hope evryone can help me with it.
Thank you in advance😀