.innerHTML stores whatever is between the start and end tags of the element as a string. Remember, if there are other elements nested within this one, the .innerHTML will contain tags.
.style.color stores the color of the text. Remember, colors are specified as RGB triples in hex, so "#ff0000" is red, for instance.
.style.background stores the background color.
.style.fontFamily stores the font "family". You can specify a particular font, or generic fonts like: serif, sans-serif, monospace, cursive or fantasy.
.style.fontSize stores the size of the font. There are several possibilities for units including pt (points), px (pixels) and em (multiple of current font-size, so 1em is the current font-size, 2em is twice the current font-size, etc).

Part 1

(look here) ← These parens are defined by this code: (<b id="tryme">look here</b>)
Enter some expressions into the interpreter to the right that manipulate the b/id=tryme element. Here are some good ones to try:

document.getElementById("tryme").innerHTML = "Hello World!";
document.getElementById("tryme").style.color="#ff0000";
document.getElementById("tryme").style.background="#ffff00";
document.getElementById("tryme").style.fontFamily = "cursive";
document.getElementById("tryme").style.fontSize = "2.0em";
document.getElementById("tryme").innerHTML = 'this is a <a href="http://google.com">link</a>';

Part 2

This box has id="box1"	This box has id="box2"	Use the interpreter below to: Give each box a different background color. Use this colorpicker to find some good colors. Add some text to each box, but remember to change the text color to something that actually shows up! Set the fontSize for one box to `24pt`.
This box has id="box3"	This box has id="box4"