trying to do SSH exercises and can't resolve host names?

Not sure if servers are even up to resolve?

Are you trying to perform the labs on the host? The labs need to be performed on the VMs. Open a terminal session on the host and type virt-manager to launch the virtual machine manager program. From there you can connect to the guest VMs.

Does that mean all exercise are done in the virt-manager instead of actual host machine? Could you confirm that please?

Yes, all of the labs have to be performed on the guest VMs, not the host.