Need RO set up help...

[GreenSpottedPuffer]

Anyone? I am going to go over to HD now. Just wanted to maybe see a picture of what I am doing so I can explain it to them easier.

Man...I don't even know what size the cold water line is

So...I am going to cut the coldwater line, add a brass "T". Off of the brass "T", I am going to add a shut off valve (any specific one?) and then that will go to the RO unit. Will I need any special fittings to go from the valve to the RO line? I guess so since there is a big size difference.

Then for the drain...I will again need to cut into it and add a "T" or would a "Y" like the dishwasher be better? With this one I know I can get a reducer that will allow me to use john guest fittings to easily attach the waste water line from the RO unit...but are they ok to use here? Is there a better way?