I would like to know how to use the app lock with just my fingerprint I use on my Samsung phone

I would like to know how to use the app lock with just my fingerprint I use on my Samsung phone what is happening it is quite irratating I use the bit defender app lock but I thought using the phones fingerprint would be enough to open up each app but after the fingerprint opens the app the app lock pens up askingme to open it up with the pin number each time this is to much as I use it a lot how can I use the app lock with just only my fingerprint only please advise in detail step by step. Thank you in advance guys