Do you have any documentation on how to use each function of Redis in Node-red ?

Hi i'm using your npm on node-red. It's really great !!! but i seem at a lost on how to use each function. for example what should i specify in msg.payload , msg.topic ??. if i want to find whether there is a key inside redis i use EXIST function with msg.topic = "Key";
then what about the other??

If you want more clarification you can tell me and i'll try to explain my problem.