How do I phrase this in my resume?

Question

I need to basically say that I was working at one branch of the public library for about a year and was asked to work at another branch for a few weeks because they were having problems keeping staff. I was referred by my boss to the manager of the other library.

So i need that conveyed in basically one or two sentences. I am 12th grade student, if that helps set the tone. Thanks!!

Answer 1

You just did it in your question. Simple, clear, and to the point is all you need.

Answer 2

Provided extended branch coverage based on top performance.