No, being a PC gamer is as simple as POINT, AND CLICK.
Use the mouse to move the target reticule at the target, then press the left mouse button!
It's THAT easy!
And now, with TF2, it's even easier! Simply pick soldier, and aim at the ground somewhat near the enemy player!
Or, pick the pyro and hold down W and M1, being sure to move your target reticule over enemies!