1. Look, then protect
Note what's there, prevent further issues where you safely can, and gather any relevant history on the space.
2. Read the house and the lot
A serious deck scope accounts for layout, required setbacks, permit conditions, footing depth in expansive clay, ledger flashing against the house, stair and guard framing, and how material gets moved through a wooded lot.
3. Put the scope in writing
Spell out prep, protection, materials, access, permits, testing, cleanup, finish restoration, exclusions, and how changes get priced.
4. Compare more than the price
Check credentials, then weigh how each proposal reasons through the job, not just its bottom line.
5. Confirm the finish
Check testing results, cleanup, documentation, warranty paperwork, and any maintenance that's now on you.