A very basic question about 433UAH config

I am new at configuring routers and will thank your help a lot!. My immediate goal is to simply being able to surf the web with my PC while getting internet signal, from my ISP´s cable/modem, through my Mikrotik 433UAH router, and the latter connected to my PC (I will later try to convert my router into an AP using an R52 radio card). The 433UAH is currently connected to my PC through Eth1 port. My PC has a fixed IP address (192.168.88.5) and subnet mask 255.255.255.0. I am currently able to get into Winbox. My ISP Ethernet cable is connected to 433 Eth2 port. Winbox shows this port receiving paquets but not sending out any.
My question: what should I do to let my PC “see” the internet conection through the router, and how to configure the router to provide my PC with an IP address (through its DHCP service)
I thank you in advance! It is no difficult, isn´t it?

Is your cable modem static of DHCP?

I believe it is static, although my PC connects to it with DHCP turned on