Hi and welcome to devnet,
There's no project builder app (unless you are referring to an IDE and in this case it's call Qt Creator)
To use the qmake provided by macports you should look into /opt/local/
However, the most straight forward way to use Qt would be to get it using the online installer. That will also provide you with the Qt Creator IDE which will be more friendly to use than the command line.
You can use MacPort to install tesseract though.
Hope it helps