Installing Magento 2.2 Theme - problem

Hi guys, Im very new at Magento and when Ive tried to install the Porto Theme, some issue happen.
At the 3rd step of install guide, I have to select the theme from Content > Design > Configuration but I cannot find the Porto theme there! Someone may know what I doing wrong? Thanks for any help!

I can offer installation service, if you’re interested in

Hi @justcats,

Welcome to the forums! If you have purchased Porto Theme on ThemeForest, you are entitled to free 6-months support:

Thanks,
Luca