To create package, use the Delphi menu File | New | Package:
Delphi will create a package, right click Contains folder and choose Add...:
Find and choose the Aurelius.Drivers.UniDac.pas file:
Then right-click the package name and click Install. You can save the package somewhere in your disk for later usage and recompilation.
About Data Modeler, indeed you have to use a x86 version of libmysql.dll file. You can use 5.7 version and the same for MS SQL, you can choose a previous version. Data Modeles uses very minimal database communication features, just to retrieve database structure.
You should also add the following attached file to the package, so that UniDac support is available at design-time.
Aurelius.Drivers.Unidac.Design.pas (755 Bytes)