Here's a quick and easy method to play whatever idea of "classic" it is that you have:
Step 1 - clone the repo:
https://github.com/EQEmu/Server
Step 2 - learn C++
Step 3 - learn MySQL
Step 4 - find somewhere to host it
Step 5 - maybe consult the wiki a few times:
https://github.com/EQEmu/Server/wiki
Step 6 (optional) - have the resources in place to prevent things like RMTing to avoid legal problems related to: gambling laws, money laundering, intellectual property infringement.
That should get you started.