If you have a blog with different articles on your start page you have to change the “content.php” in your theme folder.
On line 27 (if the file is not changed) you should change the function “the_excerpt()” to “the_content()” which then fetches the complete post until a manually set “read more” in the respective post.
That should do the trick, but maybe you have to tweak the css too (and/or your posts), to make it look good.
