A small Sandbox component named PlatformTest that moves its entity along the world X axis in OnFixedUpdate using a sinusoidal velocity based on Time.Now and Time.Delta. It is marked Hide and has an unused commented alternative to move on Y axis.
using Sandbox;
[Hide]
public sealed class PlatformTest : Component
{
protected override void OnFixedUpdate()
{
WorldPosition += Vector3.Right * (float)Math.Sin(Time.Now * 2f) * 400f * Time.Delta;
//WorldPosition += Vector3.Up * (float)Math.Sin(Time.Now * 2f) * 200f * Time.Delta;
}
}