The XML injector is a requirement for this mod. It must be placed directly in your mods folder since it is a script file. The work interactions pie menu is also a requirement for this mod.
Have you read the entire post from start to finish? I know it’s a lot of information but the mod is complex and it is important to know how it works.
To get this mod to work the Sim who you want to be King or Queen must have the King/Queen CAS trait applied.
The file is a zipped file, this means you need to unzip it. Once the file is unzipped you should see these two files that should be placed in your mods folder. Not more than one folder deep since it has a script file included. If you are unsure how to unzip/extract the folder, there's good youtube videos online or resources. The career must be applied to the Sim and since this is a gig system it might take 24 hours for some gigs to appear.
The mod will not work without the main file. It houses ALL interactions. Make sure you read the entire post and then when you reach the bottom of the post you will see the download link.
If you are not seeing the pie menu and you have the XML Injector it is possible you have a mod conflict. Remember to use the pie menu you must select another Sim (Not your own Sim). I would recommend using the 50/50 method meaning removing 50 % of your mods and see if the Royal family pie menu shows and go from there. I do not have a known list of mod conflicts.