Hi,
you should define the jndi resources within the application server and than define a datasource within the Knowage administator gui (DWH dbs).
If you want to use mysql as metadata schema of knowage the jndi resource must be called 'knowage' so the system will be able to use directly it.
More information are available at
https://knowage-suite.readthedocs.io/en/latest/administrator-guide/configure-data-sources.html
Pay attentiont that Mysql 8 isn't already certified.