To made 1 big ball (about 4" in diameter), enough for 2 kids, I measured 1 cup of flour (Robinhood brand), 1/3 cup of salt (+ a bit more), 1/2 tablespoon of canola oil, and 1/2 cup of lukewarm water.
For color playdoh, add a few drops of food coloring into the water.
Mix the flour with the salt, add in the oil, then slowly add in 1/4 of the water, mix through (flour mixture will be dry and crumbly) then 1/2 of what's left of the water, mix through then add the rest.
Knead and press in all directions, put pressure as you work through the dough. If you have older kids, let them knead the dough for you !
I found the playdoh to be really chewy (?) and soft to touch (how the kids like them). If you like it a bit more dry, sprinkle on some flour and work them through.