There are plenty of resources available for someone planning their first Camino.
There is, of course, this forum site, and someone has already pointed you to the FAQs.
There are many guidebooks. I used the
Brierly and the Village to Village guide (the latter is available as an ebook, the former only has the maps and accommodations list available in ebook format).
There are a number of useful websites and apps. If you do a search of "apps" on this forum, or in the "Equipment Questions" forum you will see lots of people's opinions on which are the best. Personally, I didn't try and pick just one of them. When I looked at the cost of the apps in the context of my overall investment in the Camino (time and money) the cost of any app seemed so small, and the weight was nothing, that I took a bunch. That way I could find out on the trail which worked best for me and I could cross-check them against each other.
Another couple of options you might find useful:
There are books (generally in e-book format) specifically for planning one's first Camino. For example, this Forum's own SYates publishes "Pilgrim Tips & Packing List: What you need to know beforehand, what you need to take, and what you can leave at home". I got a few of them on the same reasoning that I described above on apps.
I also found YouTube very useful in preparing for my 2016 Camino. There are many videos of people discussing what they took, what worked and what didn't. I also really enjoyed watching people's vlogs of their Caminos. You can find some recommended ones in these threads:
https://www.caminodesantiago.me/community/threads/camino-vlogs-to-watch.57402/
https://www.caminodesantiago.me/community/threads/best-videos-on-vimeo-or-youtube.57776/