How do I use blueprints in Factorio?

Blueprints in Factorio are saved layouts you copy, paste, and deploy across your base. To create one, select the blueprint tool from the left toolbar, then click and drag a rectangle around the buildings, belts, and tiles you want to copy; release to open the blueprint icon setup and hit Create blueprint. You can tweak the icons, give it a name, and configure parameter-based settings if you want a generic design. Once created, place it by selecting the blueprint from your inventory or from the blueprint library; the game will show a live ghost of the layout under your cursor. You can rotate with R, flip horizontally with H or vertically with V (some items, like rail signals, cannot be flipped). When you place a blueprint, construction robots can build it if you have the needed materials in your network. Blueprints can also be exported as strings to share with others and re-imported later. blueprint Importing/Exporting blueprints.

Blueprints are organized via the blueprint library (open with the B key) and can live in blueprint books to stay tidy. The library has two sections: My blueprints and Game blueprints, useful for personal vs. shared designs in multiplayer. Books and blueprints can be placed in the quickbar for fast access, and blueprints can be nested inside books. For more details, see the Blueprint library and Blueprint book guides: Blueprint library Blueprint book.