In order to create a custom caption box in WordPress you'll need to go to your dashboard. Here click on appearances, then on editor. Now over on the right select the sidebar option. Here you'll see some code, what you need to do is find the word that you want to replace on the main page, you can use ctrl+F to find the word. When you've found it within the code just replace it with whatever you want and then press the 'apply' button. You'll see that the main page will now be displaying the word you just entered. he next thing you need is a form code so that people who're interested can be captured. For this you'll have to have a subscription to an auto response service. They will provide you with the necessary codes which you have to place right beneath where you changed the first text. You can also add an image here if you want, you can do this by copying the address of the image and then pasting it within the code, where you want it to appear. It will not show up just like this though so you'll have to wrap it in the following tag for it to show,<img src="image address here">You now have your very own custom caption box.