all i understand is so surface level. vlan helps to segment network. but i am not sure how. i know vlan helps to limit broadcast domain. but i don't exactly get how broadcast storm in non-vlan network is even a thing. i read about vlan trunking but i don't really get how is that being done.

i am studying top down book by kurose ross. can anyone provide me anything? i used to love virtual machines. so thinking about pfsense, opnsense stuffs. i don't really love packet tracer as it's more like kids' toy.