You hit a keyboard shortcut, you get to the new space with 0 animation/transition. It can work with SIP on but only on macOS older than 10.14.
They mention here this is due to some changes they make to the Dock https://totalspaces.binaryage.com/sip-details I'm not sure if the only part I care about (instant Spaces switching) would continue to work without that / if you turn SIP back on. I haven't tried.