@SN-L
The ‘Entries’ metric shows the number of times a given dimension item is captured as the first value in a visit. This metric is helpful when you want to understand more about the first impressions visitors have on your site.
https://experienceleague.adobe.com/docs/analytics/components/metrics/entries.html?lang=en
That means you would need to look at this logic in data feed
post_evar should be having a value with visit_page_num =1
This gives you all the first hits when a particular dimension had value
Hope this helps