Hi, regarding your questions:
If you create and finalize the dataset, it should upload the file contents to the fileserver (or any other storage you configure). The dataset is an object similar to a task - it has a unique ID You can add metric columns to the experiments table. You can do this by clicking the little cog wheel at the top right of the experiments table. You can also select multiple experiments and compare them (Bottom left on the bar that appears after selecting more than 1 experiment)