If I had to add a data source I would review the documentation on [Creating Data Sources and Base Views](https://community.denodo.com/docs/html/browse/7.0/vdp/administration/creating_data_sources_and_base_views/creating_data_sources_and_base_views). Here you should be able to find all the information necessary to create a base view successfully.
I understand that you are on the [First steps - Connecting to Sources](https://community.denodo.com/tutorials/browse/basics/2fs5jdbc) part of the tutorial. If your problem is the driver I would review the [Installation & Bootstrapping - Pre-installation requirements](https://community.denodo.com/tutorials/browse/basics/1install_index), specially the MySQL Connector. If you follow the link to the MySQL website it will lead you to the download site of the JDBC connector that you need. On the dropdown menu that appears there you should choose “Platform Independent” and download the Zip file if you are working in Windows. Inside that Zip file you should find, among others, a file called mysql-connector-java-8.0.18.jar (or a different number, that’s just the version). This is the file you want to copy into <DENODO_HOME>\lib-external\jdbc-drivers\mysql-5.
Hope this helps!