The addon author said they weren’t going to on the curse page for it https://www.curseforge.com/wow/addons/pally-power.
I don’t think it’s possible to make it the way it was in vanilla where it could auto target and cast the buffs on different classes based on your settings and mashing one button.
You could make weakauras to keep track of your buffs maybe, or just set up various raid frames in a way to conveniently show you, but regardless of how you keep track of them you’ll have to manually target and cast. It won’t be quite as simple/fast even with mouseover macros/clique as it was in vanilla.
There’s also this addon, I didn’t use it in beta so I have no idea if it works: https://www.wowinterface.com/downloads/info25091-RebuffClassic.html