In the playoffs you have the accumulated yellow cards from the regular season, and if in the semifinals a player has a fifth yellow card, they lose the final.
At the end of the regular league of the first and second federation, the cycle of yellow cards restarts.
First Federation:
https://rfef.es/sites/default/files/images19/primera_federacion.pdf
Second Federation:
https://rfef.es/sites/default/files/images19/segunda_division_b_segunda_federacion.pdf