Problem with More and Excerpt

Hello,
I’m pretty new to WordPress, and I can’t get “More” or Excerpt to work in my posts.

I place the cursor where I want the Read More link to appear, click More and Update the post. The dotted line and “More” appear at the proper place, but when I look at the post in my blog (ProtectPlanetEarth.net/blog1/), the full post is there with no “Read More”.

Similarly, when I write an excerpt and Update, no excerpt shows up in my published post.

I’m using the latest version of the Twenty-10 theme. Please help. Thanks.