The magnetic field (magnetism is the only force that can change the trajectory of a particle, no need to worry about the electrical field) the device creates can be sloped (a slope in the field will cause the acceleration) on one side given a specific wave function (the wave function comes from what signal you put into the engine i.e. a square wave, sinusoidal, etc), in space it would be seen as a sort of induced magnetic moment (inducing a field means that the electrons in the material, even a non-ferromagnetic material such as aluminum, would be shifted to one side and cause movement) that would cause the structure to accelerate due to Lenz law (this accounts for the conservation of energy. you see others saying that this engine doesn't obey physics, which it does).

Basically saying Einstein was wrong about space time curvature (this is called special relativity which is the relationship between space and time... watch the movie interstellar to get a general idea of how that works) not being relatable to Maxwell's equations through dipole - dipole forces. ( to compare this you can look at the equation for the force between two planets versus the force between two dipoles, planets have dipoles which is why you can correlate the two- the time constraint is what provides the acceleration) Changing the unit for the kilogram to a universal constant using Amperes model (if you look up watt balance experiment it will give you a good idea as to why the kilograms unit needs to change as it is the last unit that is measured by a physical object, which is forever changing under gravity because gravity is not a constant when dealing with a moving mass) gives a whole new meaning to the gravitational constant (the gravitational constant is a physical constant involved in the calculation of gravitational force between two bodies.) and ways that it can be manipulated to be used as an engine. (The two "bodies" being the magnetic field generated and the actual mass of the engine)

I added in a bit more explanation as to what each "sciency nonsense word" actually means... it would be best for you to google each of them and get a general idea of what they do. I can't just jam years and years worth of learning into your head in a reddit post, if you are curious then you will need to go to a university and take classes in physics and math. This sort of stuff would be very easy to understand for a graduate. I apologize that you do not know, but maybe this will give you the inspiration to go study it on your own. Good luck.