Maybe I'm about to make a fool of myself again but ... If the hoses are the same as on my MK2A with its plastic air filter box ... I start with the filter end of the hose, poke and prod until it's seated in the hole in the plastic box. You could add a bit of lube there at this point, although I don't bother, it's fiddly enough without slippery fingers, but YMMV. Then I get the carb end of the hose partly over the alloy adapter that's screwed onto the mouth of the carb – the adapter has a flange, its purpose being to locate the end of the hose. The flange has two diametrically opposed slots, use the most available of those slots as a guide to feed the edge of the hose onto the adapter, while turning the hose. The last bit of the hose might need persuading onto the adapter, but by that point I find a bit of finger pressure is enough to pop it over the flange. Then make sure the hose is positioned so that the flat on the circumference of its air box end is central between the two air box holes. If my hoses etc. are different, just ignore me ...