SB1 plus Subwoofer set up

I bought two omni s2 rechargeable speakers and a refurbished omni sb1 plus subwoofer. I didn't have any problem setting up the s2 speakers using the omni app but could not connect the subwoofer to the speakers. Can you email me a link or a solution to complete my system. Thanks. FYI, I don't have a soundbar.