Reason #1 – you may not be using the wordpress.org platform. Our themes only work on wordpress.org which requires hosting. If you have not purchased hosting you may be using wordpress.com which does not allow for custom themes. See here if you need help setting up hosting and wordpress.org.
Reason #2 – be sure you are uploading the zipped files. Genesis 1st and the individual theme zipped file 2nd. See here for theme install directions.
See this quick tutorial to set you homepage to display your blog posts.
If you are using one of our themes that does indeed show post excerpts you will need to do a few things if your images are not displaying in a cohesive manner.
1. It is important to note that if your 1st image in your post is vertical (tall) it may display differently than the preview depending on the theme settings. It is best to use images with a width greater than 740px if you want them to display as shown width wise. Height will be based on theme settings.
2.. If your images are not showing at all then you will need to go into your post and in the “featured image” box over in the sidebar simply click “set featured image” and upload the image that you would like to show in the post excerpt preview. This image will not be added to your post it is only for the purpose of the excerpt preview.
4. If images are still not as you would like try using the regenerate thumbnails plugin to re-set all your image sizes.
We have a full tutorial on homepage preview images that may help, see here!