Do you want a galaxy, ready to be served?
Here is the recipe you need:
Take at least 100 billion stars and interstellar gas you desire. Add interstellar dust and dark matter, as required. Cook the mixture at a temperature of 1032K and do not forget the fundamental ingredient: gravity!
Leave it all to cool for at least a billion years... and ready! you have a galaxy that you can serve! It seems easy to create a new galaxy, but really we did not know what a galaxy was, until a very few time ago. In the past, we didn't have powerful observation instruments as today, so galaxies seemed small regions, placed everywhere in the skies and featured by a bright vagueness, called, exactly, nebulas.
...a new image of the infant Universe
...and their origin
When two galaxies start to approach, the tidal attraction forces deform their structures...
All the existing galaxies, and our Milky Way too...