I do not know what this is so can't look up what I did wrong. Also I tried to propagate by cutting off a few leaves and putting them in water but they are not doing well either. Please see photos.
What Is This Houseplant, and What Can I Do to Save It?
Certified GKH Gardening Expert
That is a begonia called "Little Darling". It looks like the soil is very wet. This is likely the cause. Make sure that your container has plenty of drainage so that excess water can run out. You will only want to water the soil when it is dry at least down to the first two inches.
This article will help you: https://www.gardeningknowhow.com/ornamental/flowers/begonia/begonia-leaves.htm