Trying to show Days and Hours in a cell

Hello, I am a very amateur excel user. I practically have never used it until I got my current job about a year ago, and now everyone relies on me to help/ show them how to use excel. I pretty much google everything but for some reason I am unable to find this answer on google.

I am trying to make a chart showing the days and hours it takes for something to be done.
I was using the formula d"d" h"h" but for some reason it doesn't work anymore. Whenever I try to add the days and hours it only adds the hours and it's a completely different hour than what I entered. I am still very new to excel so I know I very well could be doing something wrong.

Also once I figure out how to show days & hours in the cell, is there a way to sum the total of days/hours? I have looked this up as well, but I just don't understand these formulas some people send, I always get an error when entering it.

If anyone could help me, that would be amazing!


Thank you in advance!
- Your friendly neighborhood excel dumbie