Chart Tools, now you see them, now you don't

When you create a chart, Chart Tools appear on the Ribbon, which include the Design, Layout, and Format tabs.
Before you do more work with your chart, you need to know about the Chart Tools.

After the chart is inserted on the worksheet, the Chart Tools appear, with three tabs: Design, Layout, and Format. On these tabs you'll find the commands you need to work with charts.

When you complete the chart, click outside it. The Chart Tools go away. To get them back, click inside the chart. Then the tabs reappear.

So don't worry if you don't see all the commands you need at all times. Take the first steps either by inserting a chart (using the Charts group on the Insert tab) or by clicking inside an existing chart. Then the commands you need will be at hand.