Np, basically you've got a <span> which has an id of "nameAppear" which you can replace the contents of by using <<replace "#nameAppear">> <</replace>> which replaces what's in the span with whatever is between <<replace>> and <</replace>> so you're printing out "Welcome" first of all, and then replacing the "Welcome" with "Welcome $Name" which prints out the changed variable which is altered using <<textbox>>
If you want the text box to disappear, you can also replace it with nothing (or something) by creating a span around it, and then using replace.