There are a few different ways to connect T slots. The simplest way is to use a T-bar. To do this, you first need to cut the T-bar to the correct length. You then need to mark the ends of the T-bar so that you know where they meet.
You then need to drill a hole in the end of each T-bar that meets and fit the ends of the T-bar together with a bolt. Finally, you need to fit the T-bar into the slots on your machine.