First of all, please make sure your Stand List is visible on your Screen (see image below). If it is not, please see this page on how to make it visible.

Using the Stand List, click on the arrow next to the 'Filter Stand Type' selector and select the stand type of the stands you want to select, in this case I will select 'Sold' as shown below.

The Stand List will now only show the stands that have been set to Sold as shown below.

To select these stands, select the first entry at the top of the list, then press and hold the 'Shift' key on your keyboard, now select the entry at the bottom of the list and all of those stands will now be selected and highlighted on-screen.

You can now use functions such as changing the Stand Type colour for mutliple stands.