Why not just explain to them how to swing? probably would make things faster than asking them to explain it and then you inevitably correct them anyways.
Sure but if they don't even have an explanation of how it works then they're just going to tell you something like "I clicked M1 and M2 like your page said but nothing happened", to which then you'll inevitably tell them how to do it no? No offense but your game's page doesn't say anything about controls to specifically web sling. In fact nowhere in the game page does "web sling" even appear so I'm not surprised they didn't get how to do it since they don't have much instruction on how to get it done. Just my 2 cents so you didn't waste time that's all nothing more.