Are these complete sentences, or is one of them a fragment? Squidward Tentacles's teammates told him that their camouflage uniforms would never work. Especially because they accidentally used glow-in-the-dark thread.

I’m pretty sure your second sentence is a fragment because there is no subject. you say “they” but i would be more specific. who is “they”? you could also just combine the two sentences with a comma: squidward tentacles’s teammates told him that their camouflage uniforms would never work, especially because they accidentally used glow in the dark thread.

I’m sorry i don’t know how to

Sorry, what passage, i don’t see one? i can you in pm’s if you’d like.