Help with Cypripedium growing...

[The Orchid Boy]

I would like to order some Cypripedium candidum seedlings from Spangle Creek Labs. I have read a lot about growing cypripediums and how to prepare soil for them. I live in zone five and I have clay soil here. Some sites say just mix lots of coarse sand and a little potting mix into the clay soil, other sites say to get more complicated. I do live on a property that has a fair sized wooded area on it and I could get the forest floor stuff with twigs, bark, and leaves and mix it with soil or something. I would like to grow them outside year round. So could someone give me some advice please?