Creating dashboards is simply a drag and drop job. One thing you do have to make sure of is that you have created the correct report type. Tabular reports are not going to work with the majority of components unless they have a row limit, then they can work with chart or table components. The majority of the time you are creating reports to work in dashboards you are probably going to be working with summary reports as you are summarizing a certain value and then displaying these values in a bar chart, pie chart, pipeline chart etc.
To start, navigate to the reports tab and hit “New Dashboard” directly next to “New Report”. If you don’t have this button here you probably don’t have the correct permissions, you'll need to contact your System Administrator to have get access.
You will then see the layout design manager for your dashboard. On the left hand side you will be able to see the different components you can add to your dashboard. The top two starting from the left are bar charts, a line graph, pie chart, doughnut chart, pipeline funnel, scatter chart, gauge chart, metric and table.
Once you have chosen your selected component you can simply drag and drop it to your chosen column. This is the first step. The second step is to populate that chart with some data. On the tab next to components you will see data sources. This is a list of all your reports in Salesforce. Just a tip; if you are building a big dashboard it is best to create a new folder so everything is contained in one place. Once you have found your selected report you can simply drag and drop it onto the component and you’re done.
The last step is to simply customize your dashboard. If you click on the wrench (circled in the image below) within the component you will be direct to a page with two tabs.
You can change the Component data and formatting here as well as a change of graph type.