Im in desperate need of a job so should I apply to 5 different places?

I want a job. SHould I apply to different places at once? What would happen if more than one store hired me? Can someone help? Also, by having a part time job while being 16 mean you have to fill out taxes?
Update: Minimum wage here is 7.15 so that's the least i'll be making an hour right? I
Update 2: If you can, write some names of big corporations that i can apply to
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