Reading the rules before your first spin
You decide how long to play and how much to bet, but nobody can say in advance when the free spins will arrive. One session may bring several rounds or none at all. The result of any session is random, whatever RTP version runs in the lobby. Read the RTP as a long-run average over very many spins, not as a promise for tonight.
You open the game rules before the first spin, because only there does the RTP version in play appear. Fire Portals has three RTP versions, and the rules name which one this lobby runs. Compare that figure with the RTP table before you set your bet.
You plan around the top prize, yet the maximum win of Fire Portals is a ceiling that very few spins reach. Treat the ceiling as the outer edge of what the game can pay, not as a target for your session. Judge a bet by its whole range of outcomes, not by the largest figure in the table.