Litmus & Mailchimp has good tutorials, usually perfectly enough for me.
If not I just Google the question and looking at Stackoverflow discussions
One of the most popular Gifs site Giphy has that feature.
There are also some online tools and smartphone apps for it.
It's good for users but for us it's not all that great.
It would be complicated because AMP optimized emails will not work great with other email providers and Gmail isn't only email provider.
Also, it will keep visitors on their ecosystem, giving us less clicks to emails and visitors to our websites.