It's really not that hard. Poker vs humans is much more complicated than poker vs a computer.
Basically all you need to do is look at your hand. If you have a pair of the same card (two fours, or two kings, or two aces) or three/four of a kind, then discard everything else (unless you have two different pairs, in which case only discard the card that doesn't fit). If you don't, check to see if it's a straight (all the cards have numbers in an ascending order with no gaps).
If it's neither of those things, discard everything but the two biggest cards you have and hope for the best.
You can get a lot more complicated with it to nudge the odds even further in your favor but if you reliably do this you should see yourself win more often than you lose and thus you can access the rest of the game.