It took about a month of dual-use/transitioning, for me; some people can do it all at once, but some people take far longer. There are no "rules," just do it at a pace that feels comfortable for you -- no need to "stop on a dime," just keep vaping; eventually, with enough vaping, those cigarettes will start tasting like t-total crap, won't give you nearly the pleasure that a good vape provides, and you'll know it's time.
I played a little game with myself; how many smokes could I substitute vaping for? I was down to about 5 smokes a day after about a week. I also kept a "tally" sheet -- 4 verticals and a diagonal -- for all the cigarettes I smoked, and tried to go lower each day. I wasn't always successful, some days were the same number as the day before, but the general trend was less and less as the days went by.
Best advice would be: don't pressure yourself, it's highly counterproductive. Enjoy vaping so much that you actually prefer it. Anytime you feel a craving for a smoke, try to procrastinate it -- tell yourself, ok, I'll just vape now, and later if I REALLY want a smoke, I'll go have one -- that procrastination worked great for me, and as the days went by, many times I never went for that promised-later smoke at all -- BUT, if I REALLY wanted it, then I'd go have it!
Vaping needs a slightly different technique, than smoking; smoking is, hard fast draw, fast deep inhale; if you try to vape that way, you won't get a whole lot of nicotine. Vaping needs a softer, slower draw; let it hang around a bit in your mouth and throat before inhaling, or even instead of inhaling; then exhale from the nose as much as the mouth. Vaporized nicotine is absorbed best in the mucosa of the mouth, throat, and sinus/nasal passages, rather than the lungs.
Just enjoy the vape! It can completely overtake smoking, given enough time and a good enough vape.
Welcome to ECF!

Andria