Take a look at these videos in case you have not, they pretty much cover what you are looking for
Educate - YouTube
Make sure you understand the architecture
CA UIM Architecture Overview - CA Unified Infrastructure Management - 8.4.7 - CA Technologies Documentation
Basic idea of the various probes/applications UIM Supports
CA Unified Infrastructure Management Probes - CA Unified Infrastructure Management Probes - CA Technologies Documentatio…
Have a good understanding of Agent and Agent less options of monitoring , advantages and disadvantages of choosing either agent or agent less option
Basic knowledge of which OS and databases supported would be helpful
https://support.nimsoft.com/downloads/doc/NMSCompatibility_SupportMatrix_current.pdf
Probe support info
https://support.nimsoft.com/downloads/doc/Platform_Support_Availability_current.pdf
Last but not the least , understand Monitoring Governance which is the starting point of any successful implementation
CA UIM Monitoring Governance - YouTube
Good Luck with your interview