Hi,
basically what you are looking for will come down to basic EF development, so you can just go ahead and add new table to existing MonoX database, connect your table with MonoX table, generate POCOs or refresh EF EDMX (I don't know which approach would you take Code First, DB First etc.) and build your DAL. After that you can create repositories, BLL and finally UI controls.
Existing MonoX controls depend upon LLBLGen and they require you to use the generated entities. So if you want to extend the existing controls you will have to use the LLBLGen designer to do so. Please find the
MonoX DAL project on GitHub, you will be able to use the project to generate / add new tables to your DAL but you will have to obtain a copy of LLBLGen Designer from their site.
Regards