Update design-challenge.md

Author: RachHG

content/en/blog/design-challenge.md

@@ -52,7 +52,7 @@ Core users of this tool will be Researchers, mainly working in mental health rel
 
 ## Schedule
 * Challenge and Sign-Up opens: 13th January 2025
-* Online Project Orientation and Q&A Session with Harmony Product Team - **date TBC**
+* Online Project Orientation and Q&A Session with Harmony Product Team - **Tuesday 25th February 12-1pm (GMT)**
 * [Discord Channel](https://discord.gg/XPSwKzcG8N) discussions and updates - ongoing - **Product Team available directly via Discord**
 * Submission deadline: Monday 24th March 2025
 * Winners will be announced the following week on: Monday 31st March 2025