What is the order to watch A Certain Magical Index in? Including A Certain Scientific Railgun, A Certain Scientific Accelerator Anime? And all of the spin off series including Ova,and the Movies. Are they connected to the original series story line?

I ask this cause the Magical Index Аниме series is so long. And a friend told me on YouTube that he had to find a video just to see the order to watch this Anime. He was saying that some Аниме websites has the series not in order from the Episodes they aired in. So please guys and girls, please help me with the order to watch this series in. I really wanna get on with this Аниме еще than just season 1 that i watched. Thank you.To Aru Majutsu No Index. Toaru Kagaku no Accelerator.