Making the most out of my cpu - stockfish10

How to enable all my cores to work with the stockfish10 on lichess? I am using linux (ubuntu 18.04 LTS) and system monitor (linux's task manager) tells me only one of the cores is working 100% at any time- they switch. How do I make them all work?

Thanks

I'm assuming you are talking about the engine here. In this case, please see lichess.org/forum/lichess-feedback/how-to-use-wasmx#6

Buffer I have changed it and it only 2x the speed. I am expecting about 14x. your sugggestion has helped anyway. thanks