Might be a good idea to start a new thread re: the Dosbox issues, since that’s kind of a different topic altogether. Also, try using the search function. I found this just looking for “dosbox”
As for a step by step tutorial, if you search for “neogeo” you should be able to get a lot of good tutorials. Here’s one that came up when I searched.
Side note; is there an official language that people should adhere to in this forum? I just happen to know a few languages, being chinese, born in Australia, however it seems as though we are getting more and more users from non native speaking english countries.