That is a very broad topic. We can help you better if you have specific questions.
If you have never converted any Access application to any RDBMS, you are probably going to be disappointed with the results of a strait conversion if you haven't used good client/server techniques. But try it and we'll see how we can help.
There are other tools also. My personal preference is to actually PAY for tools I use. When tools are "free", YOU are the product and I don't trust them with production data. Who knows where it gets sent?