Cellar floor replacement

I would like to replace my cellar floor. currently the floor is very uneven and a mix of concrete and dirt. I don’t need to increase the ceiling height in the cellar but I would like to put in a nice flat floor so that I can use the space as a workshop. I think that what is needed is removing the old floor, then sealing it up and put in a new floor. Am I correct?

What type of contractor should I be looking for to do a job like this? Any recommendations?