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.