New to WordPress

Hi all,
I am a retired amateur webmaster chasing 70. At present I have two joomla sites (www.russellislandbb.com.au and https://www.russellislandwetlands.com.au) and one older site built in html (www.moretonbay.biz). Although I like joomla I do find it frustrating at times and clunky. What I would like to do is to move the html moretonbay.biz to WordPress CMS. My plan is to grow the site from its current 60 odd pages (Russell Island focus) to a broader Moreton Bay focus and thus many many more pages. Until a few days ago I had hardly heard of WordPress, but the more I look into it, the keener I asm to use it.
Getting started: what should my first moves be ?