setup lan hotspot

hi
I need to use the user manager for connect users to the Internet
How to set Hotspot on ether2 as,
Do not cut off users’ access to the internal network?
Do you need to build a bridge to do this?
my router : 750gr3
ether1 pppoe out connect to internet
ether2 SW internal network (wifi access point & lan desktop by valid ip or unvalid ip) in 192.168.1.0/24 reng