Calgary patios go through dozens of freeze–thaw cycles a year. The stone you see is the easy part. What keeps it flat is the part you don't see.
Start with the base
Placeholder: excavation depth, geotextile, compacted gravel in lifts.
Slope for drainage
Placeholder: why a patio should fall away from the house.
Choosing pavers or natural stone
Placeholder: trade-offs for Calgary conditions.