You can increase the number of connections in your network by pairing new Powerline Adapters or BT Mini Connectors to your existing ones. It tells you how to do this in the user guide for your type of Powerline Adapter or BT Mini Connectors.
BT Mini Connectors user guide >
Powerline Adapter user guides >
You can buy additional Powerline Adapters and BT Mini Connectors from the BT Shop >