your question is too generic to be answered.
Bluetooth provides various profiles. Moreover there is standard bluetooth as well as BLE.
So you should at first figure out:
- what does "connect" mean? (e.g. virtual serial, i.e. RFCOMM [SPP] over BT? ...)
Once you got that sorted it's probably a good idea to share a bit more details on what you want to achieve and which Bluetooth protocols you are targetting.
And then pls state your specific questions - what issues do you face if any