Okay, let's walk through an example.
For starters, pick Magnetized from the Stencils menu. The roundrect shape will be just right for this. Drag one onto the screen, and stretch it out to roughly the shape you want.
Let's add some text: Double-click the rectangle and type away. Click on the shape somewhere outside the text to finish. Next, press Ctrl-T to bring up the font inspector, and change it to whatever you like.
Now let's fix up the rectangle's appearance. Click the inspector icon in the toolbar to bring up the all-singing, all-dancing window. Hit the Style reveal triangle if it isn't open already, and you can kill the shadow with the middle tab.
The leftmost tab is for the fill properties (color). The little square to the right, next to the vertical slider, is what you click to change the background color.
I think that will do it to it. You can option-drag that finished shape to duplicate it, instead of recreating from scratch every time.
Next, to draw those lines: pick what you need (probably a plain old stright line) from the line menu in the floating toolbar up top. Back at the inspector window, pick lines and shapes (second tab) to change the stroke width and color (and make sure stroke is checked).
To avoid the magnet thingy while you're dragging the line into place, hold down the option key. To keep the lines nice and square, also hold down shift.
I think that's enough to get you going... (the description's a little verbose I guess, but actually doing it ain't so bad.)