It works like this: the type bars for the entire keyboard are divided into two groups, one in each of the "ears." When you hit a key, one of the type bars, which are upside-down-U-shaped and hinged at the bottom, swings down and strikes the platen through the ribbon. Release the key and the type bar swings back up into rest position.
Depending on whether you press no shift key, the Cap Shift key, or the Fig Shift key, you'll print a lower case letter, a capital letter, or a special character (cent sign, caret, pound sterling sign, that sort of thing). The tabs, margins, and such work pretty much like a standard typewriter.
On the earliest typewriters you couldn't see what you were typing as you typed it because the type bars struck the platen from underneath. This was done so that gravity guaranteed the bars would fall back into rest position when the key was released. All kinds of mechanisms were invented to get front-striking type bars to "go home." The result was the "visible" typewriter. The earliest visibles launched circa 1893. The Oliver company began in 1895. It appears the Oliver design remained pretty much the same through the early 1920s, though minor improvements were made. The company went under in 1928.
And, yes, it was easy to strike more than one key and make the type bars bang into each other or get jammed together. But you could do that with more modern typewriters as well.