1st step

The 'Join' brickThe 'Join' brick

Create the same construction as in the figure. Make the 'Join' brick wider by dragging in the left side.

What are 'inputs'?

Most bricks requires one or more bricks above to supply it with the things it needs to perform its job.

2nd step

Many bricks that rely on just one brickMany bricks that rely on just one brick

Create the same construction as in the figure. Go through the bricks one by one. First give focus to 'Text', then 'Pad', then 'Border'. Notice that the 'Gradient' output is used by all these bricks.

Why 'only one output'?

To make a long story short - one output makes everything simpler. A brick will pass its output to any bricks below it. Their order of appearance doesn't matter.

3rd step

No surprise hereNo surprise here

Create the same construction as in the figure. Notice that this is just a mix of 1st step and 2nd step.

What is 'many inputs/one output'?

In the real world, a car factory makes one product - a car, this is the output. Lots of smaller parts are needed from outside, so a factory needs many inputs. Similar a brick may need many inputs and always delivers just one output.