You can add workflows in the EPT in the same way as you do in the MPT or SPT. EPT workflows are prefixed with EPT.<EptName>.
You can add both Action and Time based workflows in EPT. MPT and SPT time-based workflows are executed using Value Chain Admin context whereas EPT workflows will be executed using an ENTERPRISE_ADMIN context of the owning EPT's enterprise. If enterprise admin doesn't exist, the platform will create a dummy enterprise admin context.