I have an older model sub woofer that i am trying to connect to a new receiver that I just bought. the receiver has a single plug sub woofer out line and the Sub has a 4 wire speaker wire input.
Since your sub only has speaker level connections you can't connect it the way the receiver instructions tell you. Connect it and the L/R front speakers to the same terminals on the receiver (or if it is easier directly to the L/R front speakers). When you set up the receiver set the front speakers as large and subwoofer as none. This will send the bass to the front speakers and sub. If you want to turn the sub off then you can connect it to the front "B" speakers terminals on the receiver. Make sure you keep the plus and minus connection consistent.