・・。
I ordered a book from Amazon.com.
Literal
Amazon-dot-com [at-で] book [obj-を] ordered [polite-ました].
アマゾン・ドット・コム is the full loanword rendering with nakaguro separators. 注文する 'to order' is the standard purchase verb. A minimal, practical e-commerce sentence — textbook level with no complications.