Marko, since water coming into your opening and possibly flooring your basement will be a major consideration, I would start with looking at a bulkhead door. There is one major manufacturer of these and you should be able to order one from your home center.
We put a new one in an old installation a couple of years ago but it came with really great instructions for a new install. It will give you the dimensions for rough door opening in the basement wall, dimensions for a poured concrete enclosure and the like. There are several sizes of these available and you will want to choose one to fit your requirements and work from there.