I already know that some people reading my blog might not know how to comment on a blog. Therefore, let me give some instruction.
Generally there's a "button" somewhere on the blog that says "Comments" (usually at the bottom of the post). Click on this. Sometimes you can post Annoymously (meaning the blog owner and other people won't know who posted it), but if you're going to put a name sometimes you have to sign up. To sign up with what I'm using (a google account) is FREE. You need your email address, a name and a password.
Then, you just have to look for the "comments" or "post a comment" button and go from there.
I hope these directions help, if not, talk to someone who's computer savvy. Especially if they know about blogs and have them guide you step by step.
Have a great day!