Advise on connecting speakers and sub to desktop

[Heaven Can Wait]

Hi, I am trying to connect a subwoofer to my desktop amplifier, but I am confused as to what cables I need.

The subwoofer is a JBL Professional LSR310S

The amplifier is a Fosi audio bt30d pro

And I currently have a stereo jack to 3.5mm cable connected from my amplifier to my motherboard onboard sound.
The speakers are "Lars & Ivan BoBo Designer 2-Way 35W Passive Speakers"

Could I get some advise on what cables I need to get the subwoofer working? Any if there are any recommendations to make it sound good? I have no idea what a DAC etc is. Pictures attached.

Many thanks

 

[Heaven Can Wait]

"I currently have a stereo jack to 3.5mm cable connected from my amplifier to my motherboard onboard sound."

Do you mean stereo 3.5mm jack to dual RCA input?

It looks like you need a 3.5mm stereo to 2x6.35mm mono to go from the "PRE OUT" connection on the amp to the jack inputs on the sub

Hi,

Yes, sorry. It's a 3.5mm jack going from the motherboard to a dual RCA input on the amplifier.
Many thanks for your advise.

 

[Heaven Can Wait]

Got it working with a 3.5mm stereo in the PRE OUT into 6.25 x 2 into the sub, seems very very underwhelming though if it's working as intended.