How to finish wood<br>Sand down the wood. Wood will have flaws like scratches and dents. Whether marks have come from the machines at the mills, or it has become scratched or gouged during handling, or from wear and tear.
Sanding the wood is the first step in wood finishing.
The context looks like steps from a tutorial and sanding was the first thing brought up so it must be the first step. I think it was difficult because the context never mentioned the word steps. 
( z1 sand :ARG1 ( z2 wood ) :ARG4-of ( z3 step :ARG2 ( z4 finish :ARG1 z2 ) :ord ( z5 ordinal-entity :value 1 ) ) )