To show DT Donate on your site, you do what is done with all other components... You need to create a component menu item. Here's how to do this in Joomla 1.5:
1) Go to Menus -> Main Menu (or whichever menu you want to add the new item to)
2) In the top right corner, click "New"
3) You'll see DT Donate in the list of components. Click on it.
4) Give the new menu item a Title, then make any other parameter changes according to your needs... IF any other changes even need to be made.
5) Click "Save" in the right corner and you're all set!
When a user clicks on this menu item, they'll see your donation form.