I'm assuming you're building the chart in the chart control but its data source is a report definition correct?
Then on the X-Axis, its sourced by one column and then on the Y-Axis do you want 1 line per column from the report right? If so on the Series tab you can add a new Series per column. For each series you'll want it to be a Single series with a constant label and then for the "Display values as" select the column you want the value to be populated as. This will add a single line/series to the chart. You can then repeat this for the other columns you wish to use as series values