Tanzaku theme, featured images do not work!

Hi!

I’ve been reading this forum over and over and did find a lot of solutions to make the featured images on Tanzaku’s theme work. But not for me. I used several plug-ins, replaces the ‘_content’ for ‘_excerpt’, placed codes to get the featured-image-box in my wp-dashboard. But non of them actually worked to see a featured image on the home page.

I just don’t want the first image on a post used as a thumb on the homepage. I want an image there that is not in my post.

Please, is there someone who can explain to me what to do? For now I am using the original Tanzaku functions.php and index.php with the original codes. Starting all over again.

Many thanks!