How To Program BLE and Allow Other Devices to Connect to It?

I am currently using a Bluno (Uno + Blutooth) Arduino.

I have configured the blutooth module with AT commands I found here.

When configured as peripheral, I can connect to it from an iPhone app (I believe it was called Bluno Test or something like that). However, if I were to set the BLUNO as central, how do I connect to other devices for the purpose of getting the proximity or the RSSI values (Let say I want to connect to other BLUNO or iPhone), or even scan the devices? I really have no idea as don't see it being mentioned in the AT commands list at all, or how do I do it from the Bluno itself?

Kindly advive.