How to Make Patterns That Fit My Body Type

I am determined to achieve what I intended when signing up with this site.  I am happy to learn as much as possible.  One of my problems is getting patterns that fit my body type and then having to alter them.  I would love to see a video on how to make your own mannequin to size your patterns and garments.  As well it would be helpful in learning pattern alteration tips.  Thank you and love this site and the step by step information.