Hi Stefanie,
You’ll need to put in a lot of time to get up to speed. Read up, take voiceover classes from reputable coaches, preferably those who are already working voice actors, practice profusely, listen to your recorded voice. Read James Aulburger’s book, “The Art of Voice Acting” and Susan Blu’s “Word of Mouth”. Live it, breathe it, speak it, then, when you’re ready, your coach can refer you to a credible source to create a demo. A great demo is key to attracting new prospects, but make sure the demo showcases you, and not the music and/or sound effects. Also be sure you can easily, and perfectly replicate whatever qualities the client heard in your demo when in the studio. In the “old days”, talent used to be booked directlly off their demo. Now, custom demos (raw voice) are pretty much the norm. It may be possible to use some of your best custom demos recorded for all these jobs floating around at the online sites, mix ’em up and produce them later. There’s so much more, but at least you have some “homework”, to begin. Best wishes, Bobbin Beam