You can navigate to this window by right-clicking the Report Title in the Outline View (bottom-left of screen). Database queries can be written on the right side of the default tab with fields associated with the query listed below. Ensure that a Data Adapter has been set up and chosen from the drop menu in the top-left of the window. The "Read Fields" button will populate the fields associated with your query, and also acts as a good "sanity check" to ensure nothing is wrong with the query or the data adapter.
In the query editing view, the Outline tab will display your query in outline form showing explicitly which tables and fields are being addressed by each clause. The Diagram Tab will provide a graphical diagram of the tables and fields being called and their relation to one another.
The tabs at the bottom allow even more options like adding and editing Parameters.
Navigate to File Menu > New > Jasper Report
You should see a new window with a list of templates to choose from. After selecting a template that suits your needs, a blank report template will appear in your Report Editing Area. The view will use the Design Editor Tab by default. This mode should feel familiar to anyone with experience in InDesign and other creative publishing software. Elements can be inserted, deleted, moved, resized, etc. Fonts, sizing, text color, etc. can also be chosen.
The usefulness of this view scales exponentially with the complexity of your report. Not only are all report elements laid out and organized, you can also interact with them from this view. You can drag and drop elements from other views into elements in the outline e.g. Text Field from the Palette View into the Detail band. Elements within the Outline View can also interact with each other. Moving a Query Field into the Detail band will automatically populate a Text Field containing the Query Field variable into the appropriate area of the Report, and, in addition, will automatically populate a Static Text with the Query Field name in the Column Header band. From there, you can right-click either of these elements to alter aesthetic options as well as more robust features involving formatting and other options. Most of the work for a report can be accomplished within the Outline View and by pulling elements from other Views into Outline View elements.