Tenkan Sen & Kijun Sen are buy & sell signals as well as support areas. They also point up/down/sideways to help identify market direction e.g. bullish, bearish & sideways market.
Kumo or "cloud" are the moving averages projected forward 26 trading periods so it's used to help identify if the SP is currently bullish or bearish & more importantly, which many other indicators lack, where future support & resistance will be!!
If the SP is trading above the Kumo it's an overall bullish market, if below it's bearish & if the SP trades inside the Kumo the overall market is neutral.
The trailing green line is the Chikou Span, it's the current SP projected back 26 trading periods & it helps to confirm if the SP is bullish or bearish. Also if the Chikou Span interacts with the candle sticks & Kumo it identifies resistance areas.