How to make a warp bubble moving?

In answer to this question it is stated that:

In summary, warp drives move because they already move, or else they need to propel, and their movement is not related to spacetime expansion or contraction.

This means that firstly a warp bubble had to be accelerated at some speed. The speed is higher than speed of light (this is a reason why we try to construct a warp bubble). However, how is it possible to break "light barrier"? Is it thanks to a "special" spacetime geometry of the warp bubble that allows a conventional propulsion system to break the barrier?