i didnt need to give anymore detail. Read my original post. I was not asking about anything other than a beam sensor setup.
You THINK you don't need to give more detail, which may very well be true, but without knowing the big picture we don't know whether that's the case. The more details you give, the more detailed answers you may receive, including potentially better alternatives to the setup you had in mind. The latter is especially relevant as you're new to this, as you stated yourself.
It is very common to be questioned "why do you want that specific type of sensor? Why not other sensors?". There are different beam sensors with different properties, that work well in different situations (such as indoor, outdoor, long/short distance, sensing distance or just break), so suggesting which one depends on the answer to those questions.
A beam sensor is one way to see whether a door is open, it will also detect if there's something in between (usually a good thing - but it may mess up your system if it makes your system think the door is open when it's not), but it can't detect whether the door is almost closed or fully closed.