Too cook squash on the stove in a skillet cut the squash into slices and then either add butter to the skillet or cooking oil.
You just need enough butter or cooking oil to cook the squash so just a little will do and the skillet doesn't have to be full of butter or cooking oil to cook the squash.
Once you add the sliced squash and butter or cooking oil to the skillet you can then add onions or anything else you'd like with the squash slices and then let it cook for around 10 to 15 minutes or until the squash has become fork tender.
You should also move the squash around in the skillet while it's cooking to avoid the squash from sticking especially if you're just using butter.