It's five-card draw against a paytable — no dealer, no other players. You're paid for making poker hands, and the minimum paying hand is a pair of Jacks (that's the "Jacks or Better").
Look at the Royal Flush row: it pays 250-per-coin for bets of 1–4… but jumps to 800-per-coin at 5 coins (4000). That bonus is worth ~2% of return. Betting less than max throws money away — bet five small coins instead of one big one.
This machine pays 9 for a Full House and 6 for a Flush — "full pay," a 99.54% return with perfect play. Casinos also stock 8/5 versions that quietly pay less. Always read the Full House / Flush numbers before you sit down.
Use the Machine dropdown up top to switch paytables — 8/5 Jacks or Better (same strategy, lower return), Bonus Poker and Double Bonus (big four-of-a-kind bonuses). Watch the coach: on Double Bonus, two pair only pays 1, and the higher quad/straight payouts genuinely change which cards you should hold. The advice is computed live from whichever paytable you pick.
Every deal has one mathematically best set of cards to hold. The coach computes it exactly and grades your choice — use Hold optimal to see it, or test yourself with the coach hidden.