How do I copy a build instead of placing it again, and how do blueprints work?

Steps

1. Build the thing once and make it tileable if you plan to repeat it. The blueprint tutorial builds a small shaker column specifically so that copies sit side by side without a gap.
2. Hold C and drag a box over everything you want. Both recordings that show this drag a rectangle rather than clicking parts individually.
3. Press Control C to copy. Press Control V to place. Control V again places another.
4. Press Q to open the buildings menu, then open the Blueprints tab. Your recent clipboard entries appear there, each labelled with how many structures it contains.
5. Press Save as blueprint on the entry you want, give it a name, and confirm. It now stays in the blueprint list instead of being overwritten by your next copy.
6. Press Export on a saved blueprint to turn it into a long text string, and Copy to put that string on your clipboard. Press Import and paste a string to bring in someone else's design.

Requirements / limits

• Selecting with C, copying with Control C and pasting with Control V is shown independently by three channels. That is the part of this page you can rely on.
• Control H mirrors the blueprint horizontally before placing, and has to be pressed each time you place a mirrored copy. Only one recording demonstrates this, so treat it as a single report rather than a confirmed keybind.
• Block colour is not carried through export and import. One recording exports a coloured build, imports it, and the colour is gone. Single source.
• Each save file has its own blueprint list. One recording states this directly while showing the tab; no second source confirms it.
• Nothing in these recordings establishes a limit on blueprint size, on how many blueprints a save can hold, or on how long clipboard history is kept.
• None of these recordings show a paste failing for lack of resources. Do not read that as proof that pasting is free — no source addresses cost at all.

Common mistakes

• Treating the clipboard as storage. Copying something else replaces it. Save it as a named blueprint before you copy the next thing.
• Trying to paste over an existing build. Placement follows the same rule as ordinary building: without holding Control to replace, a tile that is already occupied will not be built over.
• Copying a design that is not tileable and then wondering why the copies do not line up. The alignment comes from the original layout, not from the copy tool.
• Expecting an imported blueprint to look identical. Geometry survives the round trip; colour does not.
• Hunting for a blueprint browser inside the game. The recordings that share designs do it by pasting strings in and out of an external site, not through an in-game library.

Still unverified

• Is there a size or structure-count limit on a single blueprint?Not verifiedThe largest blueprint shown is 63 structures, which is a demonstration, not a ceiling. No source states a limit.
• Does pasting a blueprint cost resources?Not verifiedEvery paste in these recordings happens in a session where the builder already has what is needed. No source addresses cost.
• Can blueprints be moved between save files without the export string?Single unconfirmed reportOne recording says the blueprint book is per save, which implies the string is the only route. No second source confirms either half.