I can't paint, but I do enjoy it, so my advice may not be of any help.
It is not so much about learning how to apply paint to canvas, it is much more about learning how to see, how to take what is in front of you, and strip it of concept, that's not a door, it's not even a square, theres something lighter there, something darker there, maybe there's a gradient going in that direction.
Deconstruct until it becomes raw visual.
Then buy some paints (I suggest acrylics, they smell nicer and are more forgiving, and come on! 100 years lifetime is quite enough for our paintings!)
Buy some canvas, the cheap stuff.
Buy some brushes, any set will do, but you should have large and small ones.
You don't need a palette, a piece of cardboard is just fine.
Have fun! The process of applying paint to canvas is interesting in and of itself, so do that for a while before
trying to make anything that looks like something.
I'm a somewhat frugal person, so my emphasis on using cheap stuff may not be relevant to others, but for me, it lowers the barrier of entry, because I'm not "wasting" good materials, it makes me able to start a painting with less of an idea, which means more often than I would otherwise. The blank canvas is perfect, nothing has gone wrong with it yet, it is not tainted by idea.. Smearing paint onto it is destruction for a while, I will be destroying the canvas, and wasting paint until it is done, and at that point, it will have no more potential, whatever it is, it is, and it will always be less than its potential, someone better could have done much better with those materials, so they were wasted, and that is why I need to use cheap stuff, to feel less guilty about wasting them. Because I waste them purely for my own pleasure.
Here are my pictures: http://chromophiliat.dk