This can also be simply done through the StarterPlayer folder. You could also enable LockFirstPerson by selecting it for the CameraMode. StarterPlayer has many more useful options than the GameSettings menu in Studio.
For the original topic, I’d assume you need to Lerp CFrames. To lerp a CFrame, call CFrame:Lerp(target CFrame, alpha). The alpha is the “weight” of the lerp; the lower the alpha, the slower your CFrame reaches its goal CFrame.