So I take it you did not search Help, the Knowledge Base or the Community for "excel", "external analysis" or "behavioral modeling"? This question has been asked and answered before.
Here's some of the resources you need to check out:
- Solved: Controlling dimensions of parts present in an asse... - PTC Community
- Solved: How to integrate MS excel with creo 2.0. - PTC Community
- Solved: Excel Analysis - PTC Community
- http://support.ptc.com/cs/cs_26/howto/beh11983/beh11983.htm