Beginner - Help needed to block all websites except few - Firewall

Hi all,

I need some help with firewall rules i guess
I would like to accept access to a list of websites (around 60) which i have in an excel file and i want to drop all the others websites.

i have this but it doesnt work

/ip firewall layer7-protocol add name=yahoo regexp=“^.+(yahoo.com).*$”
/ip firewall filter add action=accept chain=forward layer7-protocol=yahoo
/ip firewall filter add action=drop chain=forward in-interface=ether3

Can you help me?
i just want directions.

Thanks