Thor's hammer got stolen so he went to go get it back from Thrym. Thrym told Loki that he only way Thor would get his hammer back is he married freya. So Loki disguised Thor as freya and got the hammer back.
Loki wanted to be like balder and noticed and lots of attention. Since Balder was immortal the gods practiced their accuracy on him. So Loki got mistletoe and had his brother shoot him in the e heart and killed him.
When Idunn got kidnapped with her apples of youth the gods knew Loki did something. So they told he they would give him a pain punishment if he didn't return idunn. But she returned and they continued on with their life.