If you need each of your clients to have a dedicated VLAN to isolate their networks, you can enable the VLAN Per User mode. Follow these steps to configure this setting.
Open the virtual machines page using the menu on the left and click on the Settings button at the bottom of the page. Note that this button is hidden when at least one VM is selected in the table.
Scroll to the VLAN per user section, set the checkbox to enabled state, and click save at the bottom of the page.
After making this change, all new Igiko users will be automatically assigned unique VLAN numbers. So any virtual machines they create will have virtual network adapters configured with these VLANs.