Firstly, you need to unlock a recipe for an invention by collecting all 4 pages of one Almanac volume. There are 36 pages in total, 20 in Boston and 16 in New York. To collect a page, you will need to chase after it by free-running when it blows away.

Secondly, you must have the supplies and the appropriate artisan to craft the recipe. Artisans can be recruited via the Homestead missions. This trophy is much easier when the Homestead residents are levelled up (by completing various side-missions for them) and have access to better materials.

Finally, go to either the Accounting Logbook in the Manor or any book in a General Store and craft the item. It will automatically be added to your Manor