Buttons

Have you ever noticed that some things *should* seem quite simple? No? Its just me? lol Well, anywhoo....

I know how to sew plain ole buttons on pants. However, the buttons that jeans usually come equipped with really confuse me. I understand there is basically two parts to them & that you need to coneect them together to "make" the button. How is this done tho? You find the hole the button used to be in - stick it back thru and just push the two parts together??

Am not sure I am making sense on this, so am gonna include a picture of several of these types of buttons for ya'all to look at. Would be handy to know how to do these sorts of buttons, as I seem to lose a bunch of them for some reason. Especially any decorative ones that my big butt sits on it seems lol