Hi Tina,
Welcome to this Microsoft Project newsgroup
Click Help and enter PERT. You will find full instructions and even a video to help you.
FAQs, companion products and other useful Project information can be seen at this web address:
http://project.mvps.org/faqs.htm
Hope this helps - please let us know how you get on
Mike Glen
MS Project MVP
See
http://tinyurl.com/2xbhc for my free Project Tutorials
Where can I find a step by step instruction to creating a Pert Chart in MS
Project?