A single user licence allows you to install DesignBuilder on a single computer. If you need to use the software on a second computer you can deactivate the licence on the first one and activate on the second. You can move the licence from one computer to the other freely.
When you purchase a DesignBuilder single user license, you will receive an 8-digit activation code. To use this enter it in the License dialog accessed from the Help menu within DesignBuilder and press the License button and select the Activation code option. This will cause DesignBuilder to automatically download licences for all modules associated with the activation code and activate them. You will then be able to use the software and run functionality associated with each activated license.