I think that the question is clear. I want to know the mac adresses of people connected to a certain wireless network. Thank you!
Neither method requires WEP nor WPA authorized access to the network, just proximity.
In Windows I use Nirsoft WiFi Channel Monitor to expose the MAC's on a particular AP. It's a single file/no installation truly portable app. http://www.nirsoft.net/utils/wifi_channel_monitor.html It requires MS Netmon drivers but they're free and ready to use without a reboot: https://blogs.technet.microsoft.com/netmon/p/downloads/
Kismet inside most LIVE Linux Distributions and always inside Kali gives an even broader view. From its pull down menus, select Clients view or just split the screen and scroll through the listed AP's to display connected systems and their MAC's. https://tools.kali.org/wireless-attacks/kismet