Bluetooth headphones are not displayed?

To
- in P series
1

I got a new cell phone today. Well my mother's old one, namely a huawei p20 lite and wanted to connect my bluetooth headphones (unfortunately no longer know which brand). But they were not reported to me. I restarted bluetooth and the headphones several times. With my old samsung a5, which ivh had before, everything worked out great and now they are not displayed here why? What can I do

po

When using it for the first time, you have to pair the devices with each other. With my Sony headphones you have to press the on / off button for about 7 seconds until they are ready for pairing. Then press "Scan" (or similar) on the mobile phone and then they should be displayed