The idea works on a principle of bending space in front of and behind a spacecraft. This would theoretically allow for the empty space behind the spacecraft to expand. The result would both push and pull it forward simultaneously.
White said at the conference, “There’s no speed limit on the expansion and contraction of space…You can actually find a way to get around what I like to call the 11th commandment: Thou shall not exceed the speed of light.”
NASA Physicist Unveils Warp Speed Spacecraft Design