I love, love, love Davinci Resolve (I've used Final Cut and a few other NLEs but have settled on Resolve), but be warned: while it's free, it has some pretty rigorous system requirements and you may run into problems if you're using a machine that doesn't meet its specs.
I've been doing very basic video editing in Resolve on a 2014 i5 Mac Mini for the past six months and it was fine, but as soon as I started trying to do things like optical flow (e.g., for slow motion), using power windows or gradients, or multi-node color grading, the machine's integrated graphics couldn't handle it.
If all you're going to do is basic transitions and editing, little to no color grading, applying some LUTs, etc., you can do it with most computers as long as they meet the bare minimum requirements.
Blackmagic publishes a configuration guide, which you should read to be sure your machine fits the specs.
http://documents.blackmagicdesign.co...tion_Guide.pdf
Most laptops can't handle Resolve -- sure, they'll open the app and let you do basic editing, but you'll quickly bump up against their limitations, mainly due to their low GPU memory or worse if they use integrated Intel graphics. I recently spent more than $15K to buy a new computer, color-grading monitor, and RAID array so I can use Resolve as intended.
The new version of Resolve has a much-improved audio workstation page (Fairlight) that now provides most of the functionality you'd need for post-production, including ADR (dialog replacement), submixes, effects, crossfades, EQ, gates, compression, reverb, etc.
I came to video from photography and also from audio. It's very complicated...so much to learn! Even the terminology is different from photography and there are many complex things to understand. You might want to start with some basic video courses on lynda.com. Ripple Training has excellent videos on Resolve, including a basic introduction course, but you'll want to spend a few months learning about video in general first. It's a whole different world.