No problem :) glad you are asking questions.
Filters and bubble stones/wands are very different. Filters, as I'm sure you know...filter the water and the waste out of the water which is why they are great for our fish. Some smaller tanks it is hard to use a filter because the out flow of the water will be too much for our Bettas.
If you have a filter you won't have to do as many water changes, ideally for an unfilter 2 gallon you should be doing two 50% water changes and one 100% water change every week. With a filter you can probably cut that to one 50% change and one 100% change as week. <----this is why having a filter is a good thing.
Bubble wands and stones are just to provide oxygen in the water and to get the water moving. Most Betta keepers don't use them because the Betta's like a nice calm surface so they aren't thrown around. Especially in a 2 gallon I would advise against getting any wands or stones. For those you would need an air pump, you'd have to get some airline tubing and hook the tube from the air pump to the stone. Then you'd plug it in and watch it bubble, but again, I don't advise it.
For a good filter, if one didn't come with your tank, I suggest a sponge filter. They don't cause much, if any, water movement which your Betta will like. Unfortunately you won't find them in any Pet Stores so you'll have to get those online. They can be a bit big and ugly looking but you can use decoration to "hide" them :)
Sponge filters work in a similar way to the bubble stones because you still need an air pump, airline tubing and then your little sponge that it hooks into. You can find these on Amazon if you type in "Sponge filter" and then look for a small one, like one rated for 5 gallons and under.
Hope this helps a bit :)