I am doing the "Postman API Fundamentals Student Expert Certification”, which requires to perform this particular task, where I need help in. Kindly clear this doubt.
Also, in the second pic, I have attached an error I am getting for another task. For that I inputed- {“Name”:“ABC”}, which is not showing in checked tasks.

These is a separate “training” forum here for asking those types of questions.
However, those courses are supposed to be easy to follow.
If we tell you the answers, then you aren’t getting the learning you need.
If you are struggling with a step. Go back a few steps and re-read the instructions (and visualiser on some courses).
I haven’t done those courses. I can however recommend the following.
https://www.postman.com/postman/workspace/postman-galaxy-training/overview
Start with “APIs 101 Training”, then look at the " Testing and Automation Training"
Both courses are very short but explain the basics.
From your screenshot, I’m fairly certain these courses will give the basics to be able to follow the instructions within this course.
Yes, I got how to do it.
While submitting in the ‘test collection’, I am not able to view the body in visualise mode. But since it is very long, I assume that I have a lot of errors. Is there any way other than refreshing the page, to check in visualise mode??
This is probably best asked in the training section.
If the visualiser is not working (and it’s meant to be enabled for this course - not all courses use the visualiser) then I can only assume it’s not running at all, as the visualiser is built into the API response. Otherwise, the details will be in the documentation.