Official website: pokerogue.net (no download required, works on mobile/desktop).
Open the website, pick your favorite starter, and give it a run. It takes about 5 minutes to understand the appeal. pokerogue website
Because it is a roguelike, luck plays a huge factor. Sometimes the game will generate a boss team that counters yours perfectly, or you simply won't be offered good healing items in the shop. You will lose runs unfairly. If you have low patience for "bad beats," this might frustrate you. Official website: pokerogue
Here’s a quick for new players, since the official site doesn’t have a built-in tutorial. Official website: pokerogue.net (no download required