They're three ways to place the same slider. The module is for module positions (sidebars, headers, and similar areas) set up outside the article content. The content plugin tag and the editor button both place a slider inside an article's body text — the editor button is just a faster way to insert that same tag without typing it by hand.

Fresh installs leave the System, Content, and Editor Button plugins disabled by default — this is normal Joomla behavior, not a bug. Go to System → Manage → Plugins, search "easyslider," and publish all three.

This is expected. Teaser and card-style views generally don't run Joomla's content-plugin processing on the excerpt text, so the tag can't be converted into a slider there — only the full article view is guaranteed to render it.

That's intentional. The content plugin deliberately skips rendering in the Joomla administrator — you'll only see the actual slider on the live frontend site, never in a backend preview.

Two likely causes: the Editor Button - DleJEasySlider plugin isn't published, or your site is using an editor that doesn't support Joomla's editor button toolbar (such as "Editor - None") — no editor buttons of any kind appear in that case.

Try a hard refresh or clear your browser cache before assuming something's wrong. Some of the extension's JavaScript and CSS files are cached by your browser and only refresh automatically when the extension's version changes — right after an update, a normal reload can still serve an old cached copy.

Import only accepts .json files produced by this extension's own Export feature. If the file was edited by hand, generated some other way, or is corrupted, it will fail this check

You need to check the box next to at least one slider in the sliders list before clicking Export — it exports whichever sliders you've checked, not all of them automatically.

Yes. Until you make a change on a specific breakpoint's own tab, that breakpoint automatically follows the Desktop styling. Once you edit something while that breakpoint is active, only that one setting becomes independent — everything else you haven't touched keeps following Desktop.

Yes. The underlying data structure is essentially unchanged, so this works, but it hasn't been exhaustively verified across every possible slider configuration — test with a non-critical slider first if you're migrating a large library.

Either the Content - DleJEasySlider plugin isn't published yet, or you're viewing a teaser/summary version of the article rather than the full article — content plugins only run on the full article view.