Pump internet from isp through dhcp

my isp giv’s me dhcp how do i pump my one dhcp ip into my mikrotik board and the wifi cards should give out dhcp of their own but use the internet from the one ip i am giving the mikrotik baord? i have pumped the net in to ethrenet port 3

bridge ethernet and wireless.

i fixed my issue i got a server with two lan cards i got one lan card to recive data and the other to share the net now users can login to my mikrotik and then get on the net i toke the mikrotik and pumped it in to a wifi router now the wifi router release its own dhcp like 192.168.2.2 etc etc now my second issue is that from a computer that is connected directly on the network i can remotly log in to the computer that is on the wifi router or ftp on that particular router why is that?

two more questions is it possible to pump more then one internet connection and share it on one mikrotik board and is it possible to give clients unlimited bandwith on a paticular folder and it’s subfolders like ftp folder where users can browse movies and music but at a unlimited speed like a streaming server