Cakephp3 Newbie integrate framework css

Good afternoon , I am a rookie and I have a doubt. As I can integrate another CSS framework also boostrap?
I have been reading the documentation The App View but do not understand well

I want to use MDL but I have no idea how

There’s not much to it; You can simply include the necessary js and css files to your layout.ctp, i.e.:

<?= $this->Html->css('mdl.min') ?>


<?= $this->Html->script(['mdl.min', 'scripts']) ?>

These are just sample paths of course. Note that you don’t need to add the extensions when you load your scripts through the helpers. Hope it works!

thanks you, yeah, it was really easy