I have a basic question. I am fairly new to WordPress and I have this task that I am asked to do.

I have been asked to add pages (contact, about, portfolio, etc...) to the current WordPress site that was created using the Underscores.me theme. Now my question is, can I simply access the back-end of the site and add pages from the WordPress menu or would I have to code out the page? and then assign it to a Menu?

Like let's assume I am given the back-end access, can I simply click "add pages" -> add content -> "assign it menu" -> publish?

Is that possible if the current theme was created using underscore? or Do I have to know detailed coding to achieve the task of adding a page?