UcfSE,
Ain't no such thing as "dumb" question...I worked for about 2 years before I realized that a #11 rebar is 11/8 inch nominal diameter.
Answer to your query: When, for instance, floor joists bearing on sill plate (aka "mudsill") bearing on concrete foundation stem wall, the single 2x sole plate is over the floor sheathing, i.e. at the bottom of the studwall bearing on top of the floor joists.