You could either use the language switcher component with hyperlinks, which would be the recommended way, to link to another language based page, which is addressable by a different URL.

The other way (especially for Single Page Applications) would be to use <button type="button"> elements, that have some JavaScript events attached to them to handle the switch directly. Please keep in mind to announce a change of contents e.g. to screenreaders in this case.

In both cases there's a slightly different HTML approach that you could inspect within the different examples below.

Please keep in mind that the styling is optimized to look good included within the header section of the page and doesn't "shine" included in here.