Since nobody else is being helpful. You just have two floating connections that you can use to make a wire, without the usual check that enforces you linking an input to an output. Then you can connect the other links to that.
If you're having trouble getting it to work, the 3-state buffer is how you bus. Input 1 is data, input 2 is enable. The output will match data when enabled, but when disabled, the output will be floating. Because outputs here are push-pull, if you don't use the buffer, you'll end up with bus contention. Some simulators use a pullup only system, so you might be used to all outputs being low, and the line only goes high if the enabled output is high.