How to prepare for Stamped concrete pad?

OK this one is a personal project I'm ripping up a 1500 SQF section of my yard to put in some landscaping and a stamped concrete patio and deck. I live in Southern Ontario so frost is an issue. Once the soil is removed what should I do to prepare for the concrete? Should I pack the soil? add gravel? add Chemstone? What's the proper procedure?
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