For attributes that don't apply to the concept within SMRT simulations, type the level "NA" (not applicable". Type just the two letters: NA
To import weights, use the File + Merge Variables within SMRT. You should have the weights ready in a .csv file, with CASEID in the first column.
Then, within SMRT Scenario Specification, you'll find a drop-down control on the left side that lets you choose a weighting variable (the one that you merged)