First thing if you can category to themes since this is not about installation.
Now to your issue. Its a bit hard to get to the area that needs changing without the theme code. but im going to take a guess based on a normal theme layout.
From my understanding you want to remove the date from the post cards what you want to do is looks for the section its in it could be directly under index.hbs or under partials/post-card.hbs(or something similar) that is bascialy a loop for every post around the bottom of the code you will find something like this <time datetime= you will want to remove that line.
Another thing that you can do to make it easier instead of looking all over each file to find the codes is open the theme in an editor like atom or Visual studio code and do a global search for the term <time datetime= that should show all refernces and just delete that seaction
If you want since this is looks like a quick fix if you can share your theme I can tell you which lines of code you can edit.