Switching to LESS/Bootstrap - best course of action?

I've used CSS/PHP commercially for over ten years but I feel I should perhaps look at CSS compilers and platforms such as Bootstrap. Assuming Bootstrap 4 and LESS are the go-to choices here, does anybody have a decent up-to-date crash-course?

Epic visual tool

Epson 5030UB 2D/3D 1080p 3LCD Projector Submitted April 04, 2016 at 10:50AM by DigitoCrepitus http://ift.tt/25G25D6