PIPES 101:
Items you will need:
Glass blocks
Pistons
Sticky Pistons
Chests
Repeater
Comparator
Red Stone Dust
Barrels

The amount of each item will depend on how long you want your pipe and how many pipes you are wanting. I will show you the simplest way to make a piping system.
NOTE: If you use all clear glass touching each other your items will not go where you intend for them to go.
Basics: Sticky Piston is the input. Piston is output. Glass is the pipe. Input is always chest. Output can be either barrel or chest. I use chests because we have them set as double chest size.
Now that we have that out of the way you can do one of 2 things for a signal since this doesn't tick on its own.. First is use a button or lever. With using one of those you will have to constantly click or flick it. I personally would rather have the red stone signal. Very simple to do.. 1 comparator 1 repeater 4 red stone dust.
this is your red stone signal that will only pulse when there are item in the chest.
Lets build!!! Now that you have your basic signal place a chest in front of your comparator then you place the sticky piston facing the chest, but next to the red stone signal..

again simple right!!!!
Next is laying the pipes (glass). Remember when setting your pipes that the clear glass does cross colors as we as clear.. Your pipes can be as long as you want as long as it doesn't throw errors in my console. Also, keep in mind that the more bends you have in your piping the long it is considered. So a good rule of thumb is less is better..

, next step is going to be the output.. You have to have an end location.. This is where your regular piston comes in..

. The piping does have to be on the back of the piston for it to function properly..
Finally you put your output chest/barrel..

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I tried to make this as simple as possible. If you have any questions please don't hesitate to ping me on discord.