Your title, subtitle and this very content is editable from Theme Option. Call to Action button and its destination link as well. Image on your right can be an image or even YouTube video if you like.
This is your first home widget box. To edit please go to Appearance > Widgets and choose 6th widget from the top in area 6 called Home Widget 1. Title is also manageable from widgets as well.
Elementum
This is your second home widget box. To edit please go to Appearance > Widgets and choose 7th widget from the top in area 7 called Home Widget 2. Title is also manageable from widgets as well.
Interdum
This is your third home widget box. To edit please go to Appearance > Widgets and choose 8th widget from the top in area 8 called Home Widget 3. Title is also manageable from widgets as well.