The guide to migrating is here: https://updraftplus.com/faqs/how-do-i-migrate-to-a-new-site-location/ – that guide is for copying an entire WP install, so that includes the case of copying an entire network. (It’s not yet actually possible to copy only a single site from a network).
Yes, you must first install a new WordPress site. Then you can import the backup set from the site you are migrating. You should install the same kind of WordPress site as you are copying – so if you are copying a multisite install, then you should create a new multisite install first.