When you have finished mixing your session, you probably want to export it to a sound file to burn to a CD, upload to the web, or whatever. Session > Export > Export to Audio file(s)… shows the Export Dialog to do this.

You can also export the outputs of multiple tracks & busses all at once via Session > Export > Stem Export….

File Format

This tab contains controls for the format of the exported audio file. You can enable more than one format here, in which case each will be exported in turn. Ardour is supplied with a list of export formats, including:

You can edit these formats, or create your own, with the "Edit Export Format Profile" dialog, which appears when you click the "Edit" or "New" button to the right of the drop-down list of formats.

You can also create a 'Preset' consisting of one or more formats. Ardour provides some ready-made presets, too:

Soundcloud upload

When 'Upload to Soundcloud' is ticked on in any format's tab, a pane containing fields to enter in Soundcloud account details (email and password), and what should happen to the uploaded files will become visible.

Make files publicChoose whether to make uploaded files available to anyone via the Soundcloud web site.
Open uploaded files in browserOpen each file on soundcloud in your browser after upload. If you don't enable this, you can still see the URLs in the Log window.
Make files downloadableChoose whether to allow downloading of files uploaded to Soundcloud.

Time Span

This tab allows you to select the range (or ranges) of the timeline to export. By default, "session" is enabled—this will export the whole session from the start marker to the end marker.

Channels

Here you can choose which outputs (tracks or busses) should be sent to the exported file.

Stem Export

If you chose 'Stem Export', the 'Channels' tab appears slightly differently: in this case each chosen channel (track or bus) is exported to its own file, instead of all channels being mixed together into a single file. You can choose to export either the region contents or the track output here in this case.