Make sure "File Manager" is open. Now click the folder you wish to extract and if it turns blue (as shown below) then it's been selected.
By default the settings should want to extract your zip folder in the location you uploaded the folder so when you've got the desired extracting location, press "Extract File(s)".
You will see a message like this appear whilst the files are extracting.
Once the extraction is completed and if it's a success then you'll see this message appear. Press close when it appears.