You will have to combine them if you have multiple to get the summoners level up, just like combining monster cards 😀
Or use a higher rarity summoner like a legendary if you have one, these will be able to spawn higher level common monsters
it's explained here:
https://www.publish0x.com/splinterlands/combining-and-leveling-cards-in-splinterlands-xnlxrzp
ohhh I understand, I thought the summoner was something else, but they are the cards that grant effects in general, thanks @theums