The first step is to download the extension. You need a valid and active template or developer account. Login to your JoomShaper.com account. Then from your account select Downloads, next select Extenstion and browse for SP Polls or search using the search field and then click on Download button.

Now you can install the downloaded zip file to your current Joomla, like any other extensions. 

When you have a successful installation, you'll see the following screen.