تَشَاوَرَ النَّاسُ، فَاتَّفَقُوا عَلَى الْقِسْمَةِ، ثُمَّ بَدَؤُوا الْعَمَلَ.
The people consulted, reached agreement on distribution, and then began work.
The fa links consultation to its close sequel or outcome; thumma marks a subsequent stage with a notion of delay or separation. Replacing both by simple coordination can weaken the ordered progression.
In maʿānī the ordering of clauses affects how the audience understands causation and sequence. The sentence gives deliberation, decision and implementation distinguishable places.