Where the bluetooth options on your phone will depend on your phone.

So to put the speaker into Bluetooth pairing more slide the power switch to the right hand side. If the speaker has power then a blue light to the right should light up.

Once this is done you will need to find the Bluetooth devices option on your phone. This will be located somewhere under settings - connectivity.
When you locate the device in bluetooth devices, select it then select pair.

If you can't find the bluetooth options on your phone, comment on this answer with the phone name and model and I will see if I can find out for you.