Google translate says: "guys I followed the above procedure but I can't, who would be kind enough to explain how to update AC to the spring version?"
Do you use Content Manager? If you installed as per the instructions just select the 'Spring' skin in the drop-down box (that probably says 'no active skins' at the moment) just under the little preview picture of the track on the screen where you select 'Go' to race. Hope that helps! If you've never actually used the skin though, why are you reviewing it four stars? Why not ask the question in the 'discussion' thread first, then review it AFTER you've used it?