This contest was hosted at codemarshal.org in Dhaka, Bangladesh as the nationals round of National High School Programming Contest 2017 for the senior group. It was a IOI style contest but here it is hosted as a ACM ICPC style contest. So you need to solve all the subtasks to get accepted in a problem.
Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.
If you've seen these problems, a virtual contest is not for you - solve these problems in the archive.
If you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.
Never use someone else's code, read the tutorials or communicate with other person during a virtual contest.
→ Practice?
Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.