Free version is available only for partner company associates, not for all. If you want to work on NPrinting then you need to purchase the licence or your company should be the partner company with Qlik, then only you can download it from partner portal.
I understand that you are looking for NP setup which can run in trial mode for 15 days or month or so, however there is no specific setup file of NP differentiating it for use in trial or permanent. This differentiation lies with the license.
If you are working under a Qlik Partner, you can ask your team to provide you a temporary license.
If you are working directly with a client who wants to explore NP first through you before purchasing it, then the client need to contact Qlik to get a temporary license.
If you are trying on your own as an individual then it might be difficult to get such temporary license however you can still try contacting Qlik and request one.