Peel your plantain.

Cut it into chunks; roughly a little thicker than an inch thick. (One good decent sized plantain should yield around 7-8 chunks; if you like your tostones bigger you can cut the chunks bigger)

Place them into a pan with hot oil that is deep enough to cover them. Once inside you might want to lower your temp to a medium, because they can burn quick or cook only on the outside. You want them to be light brown and cooked through before your remove them.

Once removed from the oil let them cool down to the point you can grab them.

Now that they're cooler you can squash them. Press down on the chunks of plantain one by one with the bottom of a can. (I use a can cause I find it convenient, but you can use something else with a flat surface or even a tostonero if you have or can find one at a store) They should be round and flat, but not too flat. Don't worry if they don't look perfect.

Return your tostones to hot oil until they become golden brown and crisp. Be sure to keep an eye on them, they can burn fast.

Take them out and top them with salt or adobo. (Fyi: My mother in law taught me another way to salt them. After you squish them and before you refry them you can dip them in salted water and once done you won't need to add salt. I think it makes them crispier as well.. Either way is good.)