Help with code

The photos and text on my homepage change daily. As result the description viewed on search engines for the homepage changes each day. How can I have a consistent short description coming up for the homepage when viewed on search engines?

I believe this can be done in code by using some punctation around the description, but I don’t know much about code. What needs to be done that the search engines pick up a consistent description and display it, but it doesn’t appear when a user looks at the home page? And where do I enter that code?

Thanks,