How to I stack/combine different color nodes

Hi guys, im trying to stack different nodes to alter the look of my texture. I would like to have control over its color, contrast/brightness and its RGB curves…

So im trying to group these nodes…but only the top one seems to have effect on the look of my texture at the moment…

How can I stack these nodes and make them work (i only have 1 input, for 3 outputs)

and, as a follow up question… do i put this nodegroup where it is now… or after the texture coordinate node or the mapping node?

Make it in a row.

ah that makes sense… i was overcomplicating it

one more question…
If I wanted to add a gradient to the texture… making it darker from one end to the other…

How would I set up the nodes for that…? A gradient node set to overlay (with a math node?) or something?

thank you!!

edit… oh wait…there is no such thing as a gradient node is there? What would I use for this effect?

Of course there is!! Texture >> Gradient Texture

ah yes offcourse…thank you!