Complex sentence: During the process of deployment, a truck is backed alongside the water's edge, and the bridge rolled off where it unfolds automatically, spanning 390 metres with 32 river pontoons, 12 bridging boats and four shore pontoons.
Split into simpler sentences: During the process of its deployment, a truck is backed alongside the edge of a body of water. The bridge spans 390 metres with 32 river pontoons, 12 bridging boats and four shore pontoons.