First off, take a breather my friend! I have recommendations for you.
Firstly, identify the market. Who are they selling to? The demographic, the age, novice users or not, gender, etc. Figure out who they are. From that, build your personas (ex: "John doe is a middle aged man who rarely has time to check his desktop computer, and that's why he's always on his phone - he's always on the go. He's a novice phone user, who has the best internet money can afford. He uses what he finds on your product here to share with stakeholders...").
From building your personas, you can now identify who the product is geared towards. Now comes the more in-depth discovery phase. What are these people looking for? Why are they using your product? Start outlining IA (information architecture) of your product and start designing from there. Look at what competitors are doing and how you can be different. How can you be the same. Look at examples of designs of products that are similar to yours. Take from others and use that to create something of your own.
Do simple wireframes of your product (if it's a web product). If it's hardware, work on some prototypes after sketching. You need to work on iterations of the work with your team.
After iterating with your team and creating a rough product: user test it. Get in some of the users and see what they think about your product. See what they like and don't like. Then build off of there. Once you figure that out, potentially think about launching a beta or a MVP (minimum viable product - this means something that's bare minimum but works and withholds what your clients/users will need. You can then build off of this, but at least your product is out there).
That's as much as I can help you without this becoming a huge in-depth answer. The point is, UX is not a guess. UX is not abstract. UX is designing with thought and research backed by your work. You can do this. All you have to do is research and work from that.
Hope that helps and you got this.