Whats wrong with my rotation?

It's very difficult to identity what transformation you are trying to apply, neoG457, but my guess is that you want to take the CFrame of the character's Torso, translate it by (0, -2, 0) and rotate by 90 degrees around the y-axis.

To translate a CFrame by a vector value you can either add or subtract a Vector3 value or multiply by another CFrame.

For example, if I want to move a CFrame called 'aCFrame' by (0,-2,0) I could either do:

aCFrame = aCFrame * CFrame.new(0,-2,0)

or:

aCFrame = aCFrame + Vector3.new(0,-2,0)

or:

aCFrame = aCFrame - Vector3.new(0,2,0)

To rotate a CFrame, we specify an angle to rotate by for each of the three axes: x (pitch), y (yaw), z (roll). Angles are specified in radians, where pi radians is equal to 90 degrees. You can either give your rotation as a multiple of pi (Today is pi day, by the way), or you can use the math.rad function to change degrees into radians.

So, if you want to rotate around the y-axis (yaw) by 90 degrees, you could either:

aCFrame = aCFrame * CFrame.Angles(0, math.pi/2, 0)

or:

aCFrame = aCFrame * CFrame.Angles(0, math.rad(90), 0)

You can compute a CFrame that is a translated, rotated version of a character's Torso by combining the above:

c.CFrame = Player.Character.Torso.CFrame * CFrame.new(0, -2, 0) * CFrame.Angles(0, math.pi/2, 0)

You can read more about CFrame on the Official ROBLOX Wiki.

Instead of using:

c.CFrame = Player.Character.Torso.CFrame.new(0, -2, 0)*CFrame.new(0, -math.pi/4, 0)--Notice the 2nd CFrame.new

You can change the CFrames Angles. You must use math.rad on this (math.radians), in order to change the rotation of the object.

c.CFrame = CFrame.new(0, -2, 0)*CFrame.Angles(0, math.rad(-math.pi/4), 0)

You can also do this with cameras.

This was really simple. Hope this helps!