Upload and activate the parent and child theme.
In this tutorial I will show you how to install Luanda Food.
The theme comes as a zip containing the parent theme (Luanda Food) and a child theme (Luanda Food Child). Install both, activate the child.
1. Go to Appearance > Themes > Add New > Upload Theme.
2. Choose the zip and click Install Now.
3. Activate Luanda Food Child. Keep it active so your changes survive updates.
4. Go to Settings > Permalinks and click Save Changes once.