essentially, if you have a brick named test1, if you duplicated that brick and replaced it, the next brick name would be test2. if you did it again, it's test3. etc. only applies to numerical values, and maybe only at the end of the brick name.
that still might have conflicts...
maybe you labled paddles; paddle1, paddle2, paddle3
and you duplicated them
both games with paddles would have 2/3 of the other games' paddles...