Suggestion: big, bold TLDR ("The sky is falling. Check your OpenSSL version right now") with a link on what to do sorted by OS vendor.
Step 1: Here's a command to spit out your OpenSSL version. If it is the following string, go to step 2.
Step 2: Here's how to update your OpenSSL. Here are links to guides on reissuing keys.
Probably OK the whole remediation bit links to a wiki that gets updated as the various vendors push their patches.