If you have purchased the Usage Client add-on, it is included in the License Statistics installation. It does not require separate installation. However, some configuration is required, as discussed in Configuring client applications to work with Usage Client.
The Usage Client uses a floating license, so it requires the use of an LM-X license server. The LM-X license server is included in the License Statistics installation. After installing License Statistics, start the LM-X server using the LM-X End-user Configuration Tool, as instructed in the LM-X End User Guide. (Note that HAL license considerations described in the LM-X End User Guide do not apply to the Usage Client.)