Once the map lets you make the compounds, the question turns around. Something is in the tube, and a reagent has to say what it is.
Press a cell to run that combination in the tube. The map panel switches to another part. Panels can be dragged by their header and resized from any edge or corner, and double-clicking a title pins it to the top right.
Compounds run down the table and reagents run across. Press a cell and that combination runs in the tube. The ones that change colour change, and the ones that do not stay as they were. The combinations that do nothing can be pressed as well, because what fails to happen usually settles the answer.
The silver mirror and Fehling tests both watch an aldehyde reduce something else. The aldehyde is oxidised to the carboxylic acid, and in exchange silver ion becomes silver and copper(II) becomes copper(I) oxide. A ketone does neither, because its carbonyl carries no hydrogen.
The iodoform test is not looking for a functional group but for the CH3CO- and CH3CH(OH)- patterns, which is why acetone, ethanol and acetaldehyde all give it. That methanol does not is the clearest statement of what the test means.
The purple of iron(III) chloride marks a phenol. It needs the hydroxy group attached to the ring itself, and does not appear for benzyl alcohol, where the group sits one carbon away.