Technical test are scary for someone with no prior experience. I remember my first interview. It was a live coding test and I was literally shaking. Even though I was not a junior, as a freelancer, the whole interview process was very foreign. Scary foreign I reckon.
It was so scary that I was asked simple questions like the filter method and prototypes and I just sat there looking like a fool.

I did a couple of interviews after that so I'd like to share some tips that will help you as someone who has no experience with dev interviews.

• Don't lie! If you're asked about a framework, language or methodology you don't know, reply with "I don't know but I am a fast learner".

• If a task is vague, ask for clarification.

• It's okay to make mistakes, especially in live technical test. Don't try to justify your mistakes by coming up with excuses, you'd end up embarrassing yourself.

• Nervousness is a norm in live coding (believe me) . Take a deep breath and remember it's no biggie if you don't get the job, you can apply for another one.

• If you get stuck somewhere, ask for the interviewer's help.

• And of course, be respectful and polite even if the other person is contrary.