This is where I learned how to install and use different UI's
https://www.eqinterface.com/forums/f...ce#faq_install
I also think there are UI's that are specific for P99, however I haven't had the chance to hunt them down here.
Your hotbar buttons will need to be customized, you can setup action buttons and then assign them to the hotbar buttons by clicking them and holding them then dragging to the button you want...pretty sure anyways.
This video would be good for you to watch, just someone setting up everything from scratch
https://www.youtube.com/watch?v=uSQmcHgxO2I