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 the “Product & Variants”

+ Then choose the Product

+ You can set up for all the variants or one of them

1. Short description
1. namespace: meta
2. key: short_description
3. value: description excerpt content

Result:

2. Countdown
If want show countdown on page single product, you need to enter value date time for it.
1. namespace: event
2. key: countdown
3. value: value (yyyy/mm/dd)

Result:

3. Additional Information:
Allow you enter external/Affiliate link, Add cart function will be hidden.
1. namespace: meta
2. key: additional_information
3. value: Enter information here

Result:

4. Size Guide:
If you want to upload a different size guide image for each product (clothes, watch, shoes...) you can use metafield with the name: meta.size_guide and enter image link. See screenshot below:
1. namespace: meta
2. key: size_guide
3. value: image size chart URL

Result:

The size chart will show:

5. Video
If want show video, you need enter youtube video link for it.
1. namespace: meta
2. key: video
3. value: youtube URL
Result:

6. External/Affiliate:
Allow you enter external/Affiliate link, Add cart function will be hidden.
1. namespace: purchase
2. key: on_link
3. value: [Button name]link to external product

Result
