Howdy sunvalleycenter,
Our 3.x plugin introduced a lot more powerful and easier to use API for templates. We removed a lot of the logic from our templates. With such a big update to the API, in order to use the new plugin and API features you have to fully revise the code in any 2.x template. Please peruse through our 3.0 theming guide to see some examples of a 3.x. Due to how significant these change are, and your lack of familiarity with the old API, you will likely find it easiest to perform your modifications anew with the 3.0 theme as your blank canvas. So, after familiarizing yourself with the themer’s guide you would copy the views/files you need to update to your theme directory and then modify those until they are looking right.
If you are interested in some of the reasons why the API changed, and seeing the benefits in action, checkout our announcement from May when we introduced the update.
Please let me know if that helps get you started in the right direction. I think you will really enjoy how much simpler the new API is than the old. If you have any more questions or did not follow something I said, ask away. Thanks!
– Brook