The advice is to phase up slowly, starting with one meal per day, then after a week or two adding anther meal, and then after another week or two, adding a third meal.
However, this is just guidance/advice, not THE LAW (despite what many posters on these boards seem to think) and it's perfectly your right as a parent to follow your baby's cues and feed him a bit of purée 3 times per day if he seems to want it.
How much is he having? A few spoonfuls out of a small pot?
Also, try to make sure you offer each 'meal' one hor or so after a milk feed for the first few months of weaning - milk (breast or formula) is still very important at this young age so you wanna offer this first to make sure they're not then too 'full up' of purée to drink their milk.
Fwiw, I started weaning ds1 the day he turned 5mo. By 6mo he was on 3 'meals' per day (each meal was approx one half of an Ella's pouch in quantity - although a lot of my purées were homemade).
He loved his food, is a great eater now at 2.5yo. I started introducing bits of finger food for him to play with alongside the purées the day he turned 6mo, and made the purées much lumpier too. By 8monhe was happily eating ham sandwiches for lunch, and normal fusilli pasta with Bolobnese sauce for dinner (with his hands!).
Don't listen to the naysayers on these boards who will suggest that weaning your baby before 6mo/using purées means you'll (a) get a fussy eater or (b) end up with a toddler who can't eat real food.
Just make sure you introduce finger foods from 6mo alongside/instead of purées, and start making the purées quite lumpy/adding pasta shapes at 6mo and you will be laughing!
(I found the baby led weaning cook book was a great source of ideas for finger food - and indeed nice family recipes that I could chop up and feed baby on a spoon - even though I officially speaking "weaned my baby on mush"... To use the common MN parlance!).