nanoDLP

Hi In answer to your questions
No you cant easily load NanoDLP along side your "normal" Raspi OS
NanoDLP is configured to run in what is called headless mode ...i,e,  it runs without monitor or keyboard. WHen installed it runs the OS and a webserver which is how you access NanoDLP.  It can run either fixed wire connection (on a network) or wireless. I would recommend running it with a cable first then setting up wireless.
If you want to use your Raspi for other things then a second micro SD card with a standard Raspi version of Linux is the way to go. 

Im confident that there is a way to run/ use both on one SD card but if you are just starting out with Raspi ? Nano DLP, then separate cards is a good idea while you gets to grips with Nano DLP