I’ve never mastered the finger curl but since I am a home cook without a need for speed, and have short nails, it hasn’t been a big deal. The times I’ve cut myself have been when I mistakenly left a knife in the dishpan. When prepping an onion, I halve it pole-to-pole, then peel, leaving the skin attached at the root end. I press down on that bundle of skins, which anchors the onion half onto the cutting board. With this method, your fingers are completely out of the way.
Short of a video or book, I think the most important things to know are to 1) rest the heel of your hand on the handle, while pinching the top of the blade between thumb and index finger, and 2) slide the blade forward and down as you slice; don’t use a straight up&down chopping motion. This is especially important when working on hemispheres like onion halves, where the vertical chop can lead to the blade sliding off to one side, perhaps into your fingers.
Also worth mentioning: depending on your personal preference, you can often use a coarser cut with your vegetables than the recipe or the TV chef call for. I happen to favor chunkier texture in most soups and sauces, so I generally use a medium dice rather than smaller, or brunoise, and batons rather than matchsticks. Cuts like brunoise require more skill, and higher-quality knives.