How do you make a patio with square slate stones?

Are they slate tile or actually slateslabs?.. If slate tile, they are fairly soft and should be set in or on concrete like tile. If real slate be sure to dig down several inches and pack down the area well, add a layer of sand, place the slate and fill in gaps with sand.

Hello unfortunately it’s tricky and some work to dig out and place individual stones. Each stone can be of different depths and to dig out sod, place and level takes some time and trouble. Leveling can be extremely challenging. Normally an additional layer of paver base is recommended.

In the States, gray slate stones, means slate tile.

If you mean slate pavers, as in 1” thick, then that’s something that won’t require “ too much digging and too much trouble.”

Slate is quite porous, no matter what the thickness.

So you definitely want to keep it NOT dug into the ground,

but rather well above the ground so that the water/ice/mud does not make a mess of it. As it’s a bear to clean.

Like at least 1” higher than the adjacent ground. Personally, I’d go for 3”.

Like one would do with any pavers, one would put a compacted multi layer well-draining set of pea gravel in the bottom, fine sand on top and then fine dirt over that - each layer compacted .

I would edge it, staked, so that this substrate doesn’t erode, the slate stays in its’ pen and I have a nice clean edge for the weedeater.