To connect two items/shapes within the NVivo modeller, you must first select both of them. Do so, by holding down the 'Control' key on your keyboard as you click each with your mouse. Once both are selected you can then select from the Model tab at the top of your screen the type of connector you require i.e. 'Associative', 'One Way', 'Backwards One Way' or 'Symmetrical'.

Tip: Make sure your model is switched to 'edit mode' before you attempt to change its content or format. This can be done either by selecting Click to Edit at the top of your model, or the Edit button on the Home tab at the top of your screen.