Here is some documentation that you will find useful. You should not use the 3.0 version editor because it was still in beta when Philips stopped development.
ProntoScript is not required and you can ignore it. Later, if you have some computer programming experience, ProntoScript can add a lot of bells and whistles to your configurations, but you can recreate the functionality of your original programs without ProntoScript. You can also ignore the Extenders (RFX9400 and RFX9600). Likewise, Reusable Macros can be ignored. As you advance, both ProntoScript and Reusable Macros can become very useful.
On the System Properties, select "No Network".
At this point, although the look and feel of the editor is different, your overall approach will be similar to your current approach -- all IR codes will be directly emitted by the remote.
In some cases the IR code library will be stale, but you'll find that most of the codes still work if you can figure out the nearest equivalent model. For example you might find a "Model 9" receiver listed in the database, but the current "Model 15" is not listed. In many cases you'll find that Volume codes for Model 9 and Model 15 are identical, but the command for HDMI7 did not exist when Model 9 was current. If you dig around, you can usually find these commands online. Or, you can learn the missing commands.