Let's say that creating warp gates is possible, so long as both ends of the warp gate are stationary within some universal reference frame (no time travel please). The only problem with this universal reference frame is that the galaxy is traveling at about 0.05c in this reference frame. As a result, the ends of the warp gate would need to be traveling at 0.05c relative to the galaxy in a predetermined direction.
In order to set up a pair of warp gates, you need both gates to start co-located. They can then be separated by an arbitrary distance and accelerated to the universal reference frame. Once both gates of the pair are at-rest in the universal reference frame, they can be activated, at which point they create a stable, traversable wormholes between the two gates, allowing instantaneous transit between the two.
Warp gates are expensive to create. It takes ~0.1% of the annual GDP of the species trying to make them to produce one pair of gates (wormhole containment is hard to make). Gates can be deactivated and reused, as long as they can be sent to the right place. The species in question has torch-ships that can accelerate up to or down from 0.05c in about 20 days, but can't really get to speeds above 0.1 or 0.2c.
How would an interstellar species use such devices most effectively? For efficiency here, my primary concern is the average trip time that travelers would take to get between planets (while being reasonably conservative in terms of the number of gates needed to run the system).