Keypoints and control points

HEllo good CC community,

This is a question I've been wanting to ask for a while,

Although I'm very familair with the concept of Keypoints and control points, every time I try to generate keypoints and control points to actually give scale to a reality mesh....I've been failing and I haven't been able to generate an scaled mesh.

Is there's a tutorial or a step by step that could help me?

Regards

Rafael