Rests
Just as there are symbols to represent the duration of notes, there are also symbols to represent the duration of silence. We call them “rests” and they follow the same principles as the note values. 
We can see the equivalence of symbols in the next image. 
Rests can also be dotted, and they are an exact equivalent of the correspondent dotted notes. 
If we understand the way note values work, we can easily understand how rests work, too. Rests follow the exact same principles than note values. The only difference is that note values represent sound, and rests represent silence. 
In case you want to do a review of note values, here is a list of links that can help you:
Introduction to reading rhythm
Note values and time signatures
Dotted notes and tied notes
I hope this has been helpful. Happy practice 🙂