Redirecting urls from a former (different) domain to a new primary domain

Hi Everyone! I have a question relating to redirects. 

I have a client who has a previous website on a previous domain (for example myoldwebiste.com) and now wants their new website to be on a new domain  (mynewwebsite.com). We need the previous website's page slugs to redirect to certain new website pages, so my question is:

If I have mynewwebsite.com as the primary domain, and then myoldwebsite.com as a secondary domain that points at the website, if I create redirects in the URL mappings section that use the slugs from the old website and map them to a new slug on the new website, will this work and successfully redirect them? 

I know if I just used identical slugs it would redirect to the right place anyway, but this isn't an option in some cases (i.e. where a rubbish slug was used on the old site, or where we want to redirect to a specific new/different landing page on the new site). 

I feel like this sounds obvious, and I am guessing it will work, but don't want to promise the client that until I am sure. 

Thanks so much 🙏

Amazing yes it does! Thank you so much, what a relief! 🙂