Which troubles you have with this tutorial?

Add in your custom plugin these files:

mod\your_plugin\views\default\page\elements\sidebar.php

mod\your_plugin\views\default\page\elements\sidebar_alt.php

With this content:

<?php

Flush the caches

Embed content don't use TidyPics settings.

If you talk about the bundled 'embed' plugin then you can change (by copying this file to your custom plugin with same path):

mod\embed\views\default\elgg\embed.js

Replace this string:

return match.replace('small', 'medium');

With:

return match.replace('small', 'large');

Clean the caches.

Of course,

https://elgg.org/plugins/1939398

j ' utilise Elgg HybridAuth