This is old and outdated way. Hidden features are enabled by default now
First you need Iris mini Pro. I am sorry for this, but this thing is only available in the Pro version. It costs 2$ for lifelong license and you can buy it from Buy page
If you have Iris mini Pro you need to cast your first Magical spell. In order to not add stupid things to the UI it works like this:
You should complete this spell in 30 seconds.
If you have come this far I honor you with the official Iris sorcerer badge and you can use the unofficial official hidden features of Iris mini.