[Dewy]

Take it to a reputable repair tech.

Changing the string gauge changes tension on the bridge, and if your Floyd is a full floating tremelo the springs will require adjustment, and possibly your truss rod as well.

While you could follow advice you find on the internet, you woul dbe better off reading about it, and having it done on your main guitar by a professional.

Buy yourself a cheap guitar to learn how to adjust on.