Switch is a device manage network packet between one device to another. home network today usually have router + switch together.
Beside normal packet routing, Smart Switch allow you manage filter/Vlan and QOS.
Wireless network usually use AP as switch.
The way to select switch are
1. Port number : how many device you need to connect to switch. 24 - 48
2. Function : QOS needs? Vlan needs?
3: Admin consol: remote admin ? local admin
4: security: MAC filter? address learning ?