»Client« is for wireless connection to an »Access Point (AP)«:

»Bridge« and »Repeater« modes are much the same except that in »Bridge« mode you can use different SSIDs:

As the diagram shows, other devices (security cams etc.) should be connected via cable to the CPEs. CPEs are designed for long range directional links, their antenna beamwidth is only 45º for the CPE510 and 65º for the CPE210. You will run into various troubles if you try to connect other wireless clients to a CPE running in »Bridge« or »Repeater« modes, most notably the Hidden Node Problem (google for it) and bad coverage outside the antenna beamwidth angles.
@forrest, please can you move this and the other CPE thread from MarcotteMW to the Wireless Broadband subforum? Thanks!