We have an idea of the brand new product that would solve one widespread problem among the smartphone users. But due to the fact that we don’t have required resources and opportunities to make that idea come to life, I’ve contacted the company that might be interested in my idea and would be able to realize that project. I described to them the problem and explained how my product would be able to solve it and have provided its advantages over devices that perform the same function. The COO of the company has replied and wants to discuss that idea together and assured me that it would be under NDA. Since I don’t have any prototype of my device but only the pictures of its appearance and full explanation of the mechanism, what can I ask in exchange of my idea to them? I don’t have experience in such things. As a graduate I want to offer them my idea in exchange for a chance for to work for their company and some percentage from the sales in case they decide to produce it. Does it sound possible? Should I include my conditions in the NDA? And what type of NDA should I use then? I don’t know what steps should I make now? I can’t afford attorney to help me with this.
An NDA may not get you very far--I would recommend first filing a provisional patent application, which can later be followed up with other applications as addressed in my answer to your other question. Without that protection, the company might simply say, "Thanks for talking with us, but we're already working on something using exactly that idea, so I don't think you have anything to offer us." I'm not saying they'll definitely do that, but they could if they're dishonest.
You can certainly ask for whatever you want. Whether or not they agree to your requests depends on how much they want the invention you have to offer. However, you should not try to put any conditions like those into the NDA that they will sign. At that point, they will not yet know anything about your invention, and so they'll be very unlikely to agree to any terms about it. An NDA should just be what it says: an agreement not to disclose the confidential information that is shared between the parties.
An NDA can either be "one-way" or mutual. If the company is also planning on revealing confidential information to you, a mutual NDA is probably the best approach. If the plan is just for you to tell them about your invention, then you would be fine with a one-way NDA that prohibits the company from disclosing the information you share with them.
That said, please be sure to file a provisional patent application first.