# Excel spec sheet template for input to P21 community?

**URL:** <https://forum.certara.com/t/excel-spec-sheet-template-for-input-to-p21-community/4431>\
**Category:** General\
**Created:** [October 15, 2026, 8:24pm UTC](https://forum.certara.com/t/excel-spec-sheet-template-for-input-to-p21-community/4431 "2026-10-15T20:24:34Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![Paul\_Sanfilippo](https://avatars.discourse-cdn.com/v4/letter/p/d26b3c/32.png) [@Paul\_Sanfilippo](https://forum.certara.com/u/Paul_Sanfilippo)\
**Post date:** [October 15, 2026, 8:24pm UTC](https://forum.certara.com/t/excel-spec-sheet-template-for-input-to-p21-community/4431/1 "2026-10-15T20:24:34Z")

</div>

HI All,

I’m fairly new to CDISC programming (and also coming at this from the R side of things). Im’ trying to understand best practice for creating define.xml files. I understand one can either:

1. Create define.xml once SDTM/ADaM datasets have been created, or
2. Create define.xml early on - even before the study has started - based on the CRF.

The second option seems more appealing from a planning POV. To do this it seems you can create an Excel spec sheet for the various metadata components of SDTM/ADaM (separately), pre-populate manually, then input that to P21 community, and create the define.xml from there. If that’s the case, is there a template somewhere for the recommended structure of the Excel file (e.g. showing sheets required, their names, variables required in each sheet and their names)?

Thank you!

Paul