The OfficeWriter Designer .NET for Excel

The Open button provides the option to Open From Disk and Open From Server

Open From Disk: open an RDL file stores locally on your machine.

Open From Server: Download an RDL file from a report server.

The Save button provides the option to Save to Disk and Deploy to Remote Server.

Save To Disk: save your template as an RDL file.

Deploy To Remote Server: Publish your report on the Reporting Services server. 
Once you do this, your report will be available for viewing in Excel and through
Reporting Services Report Manager.

The Import Template button allows you to import an existing XLS, XLSX, or XLSM file
and use it as the template for the RDL. This will remove any existing design information.

The View button sends a request to Reporting Services to run your report, then
displays the results in another window in Excel. If you click this button with an
unpublished report open, you will be prompted to publish before viewing.

The Data Markers button provides a list of all the data sets in the RDL file.

Navigating to and hovering over one of the data sets will expose the fields in the data
set query. Clicking on a field from the list will insert the data marker for that field into
the current active cell.

The *Report Properties* button will launch the Report Properties dialog.

The Help button provides links to information about the OfficeWriter Designer toolbar.

About OfficeWriter will display the version of the Designer toolbar.
OfficeWriter Documentation is a link to the OfficeWriter Docs.