How to ask for additional position at work?

So I started at Target, started from 2 weeks ago. They've recently announced that there are some other positions to be filled and asking Employees to train for other areas, if they want for extra hours.

I want to take this opportunity and I'm wondering whats the best dialogue to go about asking the person in charge.

I wan't to know how you would approach this situation.

Also needing help finding a word.
Phrase goes like this.
" I want to try my (Word) in that Area "
It relates to the word Expertise but in a more casual meaning.
Something like: "I want to try my (Gull?) in that Area" but I'm afraid that might be entirely incorrect.
Asked Mar 31, 2016

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