Fixing substantially warped table top planks
Have a bonfire and go buy some straight 2x4's (those certainly appear to be 2x4's)
Or possibly some nicer wood, depending what you intend for this table. My eyeball assessment is that this is ordinary framing lumber (&quot;studs&quot;) which is commonly &quot;spruce, pine or fir&quot; and nothing special to look at.
Salvaging what you have will be tedious frustrating and largely pointless, IMHO unless this particular collection of wood has huge sentimental value.
The only &quot;get rid of the twist&quot; method I can recommend is to remove wood until the boards are thinner, but flat. That is a somewhat challenging prospect if you have limited experience with woodworking. Wetting generally only makes a difference while it's wet, and when it dries out it goes right back where it was. Steaming is a huge operation, then you need to move the wood somewhat beyond where you need it to end up, as it &quot;springs back,&quot; and clamp it there until it cools and dries. If you have correctly guessed the amount to overcompensate for the current twist and bow you might end up close to straight.
Meanwhile, you could have had that bonfire and gotten some straight dry wood...