Place the particle balls above the line and press play to let physics do it's work. Balls of opposite polarity annihilate each other. To clear the level there should be no particle balls remaining.
To install a piece of the bridge, click on a green anchor point where you would like it to start and draw a line to where you want the piece to end. To remove a piece of bridge, scroll on top of it and click the left mouse button. To delete multiple pieces, click on the junction between them. Click and drag to scroll around the level. To zoom within the level, use the + and – buttons.
Reach the portal somewhere inside the level. Use the arrow keys to move. Press space or D to jump. Pressing A will let you switch between the layers. Press S to pick up an item.
Blow up the building so no rubble remains above the set line. Use the mouse to place the sticks of dynamite on the beams. You can only place one stick of dynamite per beam and only on the concrete ones. Some levels require you to make sure no rubble touches an adjacent building.