I would be surprised if your kit included a proper snow foam lance, probably just a foam attachment which not necessarily the same thing.
All the foams I mentioned in my previous post are good. You need to use about 1" snow foam solution in the lance bottle, then top up to nearly full with warmish water and attach to your pressure washer. Each lance has a thickness/dilution adjustment and spray adjustment and you'll need to mess about with both these to get a good snow foam consistency. If it's too thin, it'll just run straight off, you should be aiming for a thicker foam that will cling for a few minutes.