Tower Defense Game; One timer for all units' movement.

I'm creating a Tower Defense game for a 2 month-long project in my Computer Science class, and I created about 10 timers for a unit (just a square) to go through the map. Instead of repeating the 10 timers for each unit, I tried making a variable and just replace a variable. (for example, I tried doing 'varEnemy.Left = varEnemy.Left + 241' then declare 'varEnemy' differently for each unit.) If there was a way to do this, it would be an IMMENSE time saver, as I have many units, waves, and levels.

Thanks for the help,
AhellHoound