How can I approve bluetooth dongle adapter in my jbl bluetooth headphones?

[Windows Central Question]

Hi, I bought a new jbl bluetooth headphones and I didn't notice that it have no aux port.
I want to connect it to my old mp4 via bluetooth aux dongle adapter. The problem is that i have no buttom to accpect the devices cuz they have no screen and they are only scanning for devices and not catch them.
Headphones model: jbl450bt

Any suggestions please?