the liquid part, u just need to let the liquid flow into the plenum chamber tru the vacuum hoses. so that the liquid can clean those dirt in the plenum chamber down tru the runners, hopefully some at the valves & combustion chamber as well. for an easier alternative, u can just fill those fuel system cleaner in ur fuel tank, but by doing the 1st method, its more concentrated ler.
but if u ask me, honestly speaking. i still think the best way to clean the TB & intake manifold is to dismantle them and clean it individually with diesel. guarantee 100% clean, not clean u can scrub it until clean. only thing is, very time consuming. injectors u need to send to shop tat has injector cleaners like GT auto or N1 in sunway. they use ultra sonic waves to break anything thats clog in the injectors.