Part 1
Be a member of this group

Part 2
Donate cases and or keys
http://psteamcommunity.yuanyoumao.com/tradeoffer/new/?partner=92881115?partner=92881115

Part 3
Watch out not all keys and cases are accepted

Part 4
This are the ACCEPTED cases and keys
Huntsaman Weapon Case
Operation Phoenix Case
Winter Offensive Case
Operation Bravo Case
Red Esport case
Blue Esport Case
and the keys to come with these cases