This achievement will be done on level 2, where you fight Arclight, which has the signature move of the 'Slam'.

Now, this might seem easy to get, but if on a higher difficulty this can be some what of a hassle. So I would recommend playing on Easy.

Her Slam move, is basically when she jumps up and shoots at the ground creating some what of a blast. This can be easy to avoid if you just constantly keep pressure on her and consistently avoid her attacks using B. And you may find if you continually hit her while she is in the air, she will lose a lot of damage before even having a chance to attack.

You shouldn't have too much trouble completing this, but if you by chance have the slam move done on you, you will need to reload the checkpoint and try again.