I am a total noob when it comes to solid works but i am in desperate need of help as i have tried and failed a couple times now!

I am working on a project where i am recreating a soda cup lid (like from mcdonalds). These lids have triangles securing them to the cup which i am trying to recreate and i just need help with how to attach this shape to my model.

On the third picture i uploaded you can see the patterned sketch that i am trying to add to the inside of the lid, i tried using "Projet Curve" but i got an error message: "Rebuild Errors"
I have noticed that sketch25 is under defined but i am not sure how to fix that.