On the theme, cannot show the countdown on Collection. However, you can use this app to do it: Metafield Guru
+ After install app, go to App and config for it.
+ Choose Collections option
+ Then, choose the Collection which you want to show countdown:
+ Write as this image:
- Key: countdown
- Namespace: meta
- Value type: String
- Paragraph: write the time countdown
+ Go to View to see the result:
Thank for reading!