You have two choices: 1) the data is stored inside the chart, or 2) the data is in a Writer table.
For case 1:
Insert > Object > Chart. A chart should appear using a default data set. You can change the data by View > Chart Data Table
For case 2:
Insert > Table... enter your data
Select the table cells containing the data you want in the chart
Insert > Object > Chart. A chart should appear using your data set, and a "wizard" will guide you through customizing the chart settings.
AOO 3.4 • Linux • Fedora 17