Gently scoop some water from a puddle or a pond with your cup, try to get as little dirt as possible into the cup. The more dirt comes along with the water the faster the filter becomes clogged and can no longer be used.
Pour the water from the pool or pond in top of your water filter, catch the water at the bottom of the filter in a clean cup.
it is best to throw away the first bit of water that comes out of your filter it often is cloudy and not that clean.
If the water that comes out of your filter is clear it is good and you can use it.
Boil the water at least 1 minute before drinking it, cooking will kill bacteria and viruses that are still present in your water.
If you put some spruce needles in the boiling water, you'll also have a tasty tea.