CFrame is a hidden property that uses only Position, and Orientation (aka Rotation) which is probably why it's hidden.
Lets start with changing position with CFrame. It's just like how you would with the position property, but instead of Vector3.new() it's CFrame.new()
game.Workspace.Part.CFrame = CFrame.new(0,5,0)
Moving on, we have orientation. This is how you change orientation with CFrame.
game.Workspace.Part.CFrame = CFrame.Angles(0,math.rad(45),0)
The reason we use math.rad() is because you have to change the rotation in Radians, not Degrees. math.rad() takes a degree value, and returns the radian conversion of it. There's a way you can change Position, and Orientation with CFrame at the same time! here's how you do it.
CFrame.new() has a bunch of different arguments: CFrame.new(x,y,z,r00,r01,r02) there are other ones, but these are the ones we need to know.
game.Workspace.Part.CFrame = CFrame.new(Vector3.new(0,5,0),Vector3.new(0,math.rad(45),0)
And there you have it. The CFrame Basics. I will be make a part 2 to show some other stuff about CFrame.