I would like to paint concrete floors. What is the procedure to get them to look like hardwood floors?

Not so simple as a 'procedure.' You need to know what's under the concrete, and if you don't know, you need to do a moisture test. Concrete poured before the 1980s isn't too likely to have vapor barriers and insulation foam panels. You can cut a big square of heavy mil plastic and duct tape it to the floor for 2 days to see how much moisture collects under it, but that won't tell you what all times of the year are going to be like.
Personally, I would not use paint on concrete. Concrete never really sits still. It effloresceses not matter what, and the efflorescence takes the paint right along with it.
There are colored stains (that can't peel) but they won't look like hardwood.
There are laminated planks that are printed woodgrain that looks very much like real wood (as opposed to engineered flooring, using real wood veneer, that won't stand up to the moisture). You put the planks down in a 'floating' floor, no nails, over a heavy mil plastic and thin insulation foam, which can be bought as one piece. It must be taped at every seam before putting down the floating floor.

That's what I would do, and laminated can get down to about 65 cents a square foot, plus the cost of the vapor barrier. There are ceramic tiles that look like woodgrain, but they are more costly.

If you are trying to save money, just buy a tinted stain and a few synthetic scatter rugs and don't try to pretend it's something it isn't.