When used before the three motion verbs 来る(come), 行く(go), and かえる(return), the te-form of transitive verbs indicates an action performed before moving(i.e., coming, going, and returning). The structure is the same as the one which has just been introduced in Lesson 17-6.
アリさんは 国で 日本語を ならって 来ました。
Ali learned Japanese in his country, and [then] came to Japan.
わたしは 日本で おみやげを 買って かえります。
I'm going to buy a souvenir in Japan before going back to my country.
ここに にもつを おいて 行きましょう。
Let's leave our things here [and go].
Lesson 11-8「日本へ かぞくの しゃしんを もって 来ました。」
I brought photographs of my family to Japan.