Gardening

I live in a place where about 30 cm down is sandstone/mixed sandstone and sand.

I want to buy and plant some established saplings in the 50L-100L pot range and plant them where I recently had to remove some sick/invasive trees.

The area is a raised garden bed with a stacked rock retaining wall, so the ability to get power tools in is quite limited. A jackhammer could probably be brought up there, but that's about the limit. I also need to remove some partially rotted stumps at the same time, however a stump grinder could not to brought to the area :(

Basically how fucked am I? Does anyone having experience in digging in soil like this have tips? Anything from what tools to use to specific technique to avoid wasted effort or hurting yourself. I'm relatively strong for a woman but not a powerlifter or anything so shape your recs around that degree of physical capability.