This wiring will prevent the battery power from dropping and therewith a restart of the connected running computer.
Note : With modern Automotive-power supplies (eg. M1-ATX, M2-ATX, M3-ATX, Infill G4, etc..) a backup battery is not needed ! These power supplies are able to compensate all power drops alone !
The "Backup-Battery Setup Guide" is no shipable product. The "guide" is the picture you can see above !