The best way to learn is to copy what others have done.
Take the banner code that the site offers (I can see that you've done that with a couple of other sites already) and just replace it with your banner information.
For example..one of the codes says this...
a href="http://www.lonestarclicks.com/pages/index.php?refid=velvettami" img src="http://www.lonestarclicks.com/images/banner.gif" border="0" alt="Lone Star Clicks.com
The img src there belongs to lonestarclicks.com...linking to that site is considered bandwidth stealing. So what you would do is...download the banner from Lonestarclicks on to your harddrive. Then upload it on to your website. Now you've got a new code for it..that isn't stealing. Since it's on your website...you no longer need the http:// stuff...you can just put lonestarclicksbanner.gif after the img src= tag. (or whatever you decide to name the banner) If you've got your images in an image folder on your website..the url would be images/lonestarclicksbanner.gif.
The new code would look something like this...
a href="http://www.lonestarclicks.com/pages/index.php?refid=velvettami" img src="lonestarclicksbanner.gif" border="0" alt="Lone Star Clicks.com
I noticed on your website that you have a broken image...when I look at the properties...this is what it shows
http://www.velvettami.150m.com/Country%20G...den%20Email.gifIt's best not to have spaces in your image name...that's what causes the 20% thingys. I can't tell if this is what's breaking the image or not..but it looks weird! Make sure it's all one word.
Also...you have the site url as this...
http://wwwcountrygardenemail.comlBe sure to check your spelling and stuff..or it won't work! If this isn't site..you'd be missing out on referrals also..because their no referral code on that url...there is always a url to use on the site that you want to link too.
I hope some of this is some help to you. I think I confused myself just trying to explain it!

If you need a professional...check out www.lissaexplains.com This girl has everything you could possibly need on HTML!
Good Luck!!