I would like to create the drop down filter search from my wix database, but I dont know how to do that. I saw some youtube video before, but those video are few years ago and the wix interface seem different to now. Thank you so much.
How to create your own FILTER-ENGINE, you can learn from example here…
https://www.media-junkie.com/databases
https://www.media-junkie.com/pflegeservice
I hope this is not too complex for you (it will be a long way to realize it if you are a totaly beginner). But if you read all the related posts, which are given in this interactive example, you perhaps will be able to create your own FILTER-ENGINE / SERACH-ENGINE.
You should start with the ORIGINAL-POST.
Good luck and happy coding 
Have a look at this API: https://www.wix.com/velo/reference/wix-dataset/dataset/setfilter
If this is to complicated for you, you can hire a Wix partner to do it for you