up and at 'em
Get going, get busy, as in Up and at 'em—there's a lot of work to be done. This colloquial idiom, often uttered as a command, uses at 'em (for “at them”) in the general sense of tackling a project, and not in reference to specific persons.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.