help on Making the famous aqua gel text tutorial

hi, i need help on "Making the famous aqua gel text" tutorial
on step 2, it says "Go to select/modify/contract and use a value of 5. With the selection still active fill the layer with the lighter blue color (name this layer multiply). " how do i fill the selection?
if any one can help, please reply asap

go to edit --> fill.

or select your foreground color and press "alt + backspace".
next time use the help-function of photoshop please.

thanx