Tips on singing in chest mix (belting)?

Hello everyone! I wasn't sure where to post this, so into ~misc it goes.

I'm currently looking into auditioning for a professional musical theatre production. Now, being a baritone (E2-C5) would kind of put me at a disadvantage as most musical theatre roles are for tenors, but I found a musical soliciting online auditions for baritones. Usually with musical theatre, they don't really care about your voice type; they care more about your vocal range. "If you can sing it, you're more likely to get the role."

Anyways, my passagio (or vocal break) is around E4 and the audition (and therefore the musical) is requiring me to sing a G#4. I know that I'd be able to sing it because a) my range can do it and b) I've belted probably incorrectly an A4. I've never really had to use my chest mix range before, so would anyone have any tips?