how can I connect to a wired DSL modem and APC battery backup BN1080G?

Presumably I need to connect the computer and the ZyXEL P-600 series DSL modem (from Earthlink) to the APC battery backup BN1080G not only for complete surge protection, as I do on current computer, but also because the HP ENVY Desktop 750-114 lacks the connections to directly connect phone lines to it anyway (or cable jacks for ISP modems that require coaxial cables for computer connection). I'd try just copying how current computer is connected but it's unclear whether I can do this or which of the phone line ports to use for the wall outlet line and which to use for the phone line between modem and the APC battery backup BN1080G whose phone line ports are labeled differently than previous APC battery backups I've had where one was labeled Wall Outlet (line from phone outlet goes here) and one was labeled Modem/Phone/Fax (line from DSL port of modem goes here). The BN1080G phone line ports are just labeled IN and OUT with literature information stating, "(Use a telephone or network cable to connect a cable modem to the IN port, and connect a computer to the OUT port)". Don't know why it specifies "cable modem" or connecting a computer to OUT port when there should be no direct phone line connection to computer even when possible. Modem also has an Ethernet port with appropriate cable to plug into computer's Ethernet port and the modem's power source is plugged into backup battery, of course.

Do these outlets work same as previous ones for phone line connections? If so, which line in which port and does this apply to HP Envy Desktop 750-114 setup?