You still need a filter IMO. Try to find an Azoo mini filter. You need to feed the bacteria. It's actually from the air. You'll need to add a food source, a drop of ammonia or a pinch of food every day until you can add fish when you're done cycling. Get a test kit with ammonia, NitrIte and NitrAte bottle (strips aren't as accurate).
You can wait a few days, then start testing the ammonia and nitrites. The ammonia should go down to zero and the nitrites should start climbing. The NitrIte phase can last quite a while. Start testing for nitrates about a week in. When your nitrites reach zero and you have nitrates, you are fully cycled. Get a Get a piece of tubing to use as a gravel vacuum, change a gallon or so every week. You're set. I don't keep plants, so you might want to go to that section for expert advice there.
I'd stay away from snails. The smaller ones can over populate quickly. The apple snails make a lot of poo and are usually pecked by bettas.