To view the attached comments to a post:
Click / tap
1) text of the gab post
2) timestamp in the post box
3) small 'comments' under a post.
In your notifications area, a repost or quoted post may not have text to click on. In that case, please click the time stamp.
If there are comments attached, it will be reflected with a number counter. If there were no previous comments, the option won't be visible.