I assume you are creating an MS Access report.
You have the data you want. You need to create a group on the client number.
Select the detail section of the report design, click right mouse, and pick “sorting and grouping”. In the field or expression column, select the client number field. For group header, say yes. Close the dialog. Move the client number (and related fields) to the new group header section.
By the way: MS Access installs with a sample database: Northwind.mdb. This should get your creative juices flowing.