Hi mate. You choose the wors way to ask for help regarding Blender. I didn't watch Piero training but it has to be 1 of 3 options: the bones are not parented to ones they need to follow, they don't have suitable constraint or they are already in IK constraint chain with another target to follow. Here: [login to view URL] You can dowlnoad Piero rigg and check, what You're doing wrong. On this site You also will get the answer on Your question, if You ask and upload the .blend file, You're working on.
Don't award me with this job. It's a free advice :)
Regards,
Marek