What was the context of President Roosevelt's Fireside Chats?

He gave them when he was first campaigning for president to convince Americans to vote for him.

He gave them once a year to Congress and they were then reprinted in newspapers for all to read.

He gave them regularly during the Great Depression and World War Il when the nation was in crisis.

He gave them after World War II ended to explain how the U$.$S$.$ would help rebuild Europe.