Wan and Lan

Hello, Im having a problem here
WAN IP:
PE: 120.28.34.249/30
CE: 120.28.34.250/30


LAN: 203.177.50.96/27
Usable: 203.177.50.97 - 126

What should be the configuration in mikrotik for me to be able to use the usable I.P addresses.

When I directly connect a computer to Modem, and use Wan Ip. It has connection but when I used the usable IP address, there is no internet connection

My guess is that LAN addresses are routed to you by ISP using your WAN IP as gateway.

The simplest way of using LAN interfaces would be to assign one of LAN IP addresses to LAN interface of router and use the rest for clients (either put them to DHCP pool or configure client devices statically). Either way the devices should use router’s LAN address as their default gateway.

help pls. ty