Learn Arabic (Modern Standard): النجار يصنع كرسيا من خشب.

In Arabic, sentences can start with a verb (verbal sentence) or a noun (nominal sentence). Both are grammatically correct. Starting with النجار puts a slight emphasis on the person doing the action. The standard verbal sentence order, starting with يصنع, would also be perfectly fine.

Why is there an extra alif at the end of كرسيا (a chair)?

The word كرسيا is the object of the verb (what the carpenter makes). Indefinite objects take an 'an' sound ending called tanwin fatha to show this grammatical role. When writing this specific ending, Arabic spelling rules require you to add an extra alif to carry the marks, unless the word ends in a taa marbuta or a hamza.

The English translation says 'of wood,' but doesn't من mean 'from'?

Yes, من literally means 'from.' In Arabic, when you describe what material an object is made out of, you use من followed by the material. So من خشب translates literally as 'from wood,' which is the natural Arabic way to express 'made of wood.'

Does the word for carpenter, النجار, follow a pattern I can use to learn other words?

Yes! Many professions in Arabic follow a specific pattern that doubles the middle root letter and adds an alif. The root here is noon-jeem-raa, and applying this pattern gives us نجار (carpenter). You will see this same pattern in other job titles like خباز (baker) and جزار (butcher).