There are many posts on how to configure Mikrotik especially for hotpsot server. let's make it simple, i will show you step by step configuration to create hotspot configuration in mikrotik. I'll assume you that you are familiar with mikrotik.
1. After connected to the mikrotik, with mac or ip address, go the interface menu, and please rename your port that will be used. For example port 1 will be using for internet/wan/isp, and port 2 will be using for hotpsot lan.
2. To ensure that the mikrotik received internet form isp, so you must setting DHCP client to get ip public dinamic and your mikrotik will connected to the internet. Click IP >> DHCP client. Create new, interface: port1(isp). ok.
3. Makesure with ping to google.com.
4. Setting DNS, you can fill with DNS google, like image below.
5. Please give this mikrotik with ip address. IP >> Addresses. Create New, and fill the the schema address like what you want. For Example, 192.168.10.1/24 set for interface port 2(hotpsotlan).
6. Go to the IP >> Firewall >> NAT. Create New and leave the configuration as default but change the action with masquerade. OK
7. Go to IP >> Routes. New Route and fill the destination address with your network 192.168.10.0/24. Gateway is from port1. OK
8. Last step is very important think. Go to the IP >> Hotpsot. In server, create new, and choose the interface for port2(hotpsotlan). Just next and next..:D until finish.
10. Edit server profile, and choose you login page design, dns name(forexample: hotspotlogin.com) and make sure that you alreade uncheck cookie from option menu.
11. Just go to the hotspotlogin.com in your browser, Finish.