3 sentences

1. 他在网上找了一个韩语入门教程。

   tā zài wǎng​shàng zhǎo le yī gè Hán​yǔ rù​mén jiào​chéng.

   He found an introductory Korean tutorial online.

   Source: Dong Chinese Dictionary

2. 如果你想学习围棋，这本书是很好的入门教材。

   rú​guǒ nǐ xiǎng xué​xí wéi​qí, zhè běn shū shì hěn hǎo de rù​mén jiào​cái.

   If you want to learn Go, this book is an excellent introductory textbook.

   Source: Dong Chinese Dictionary

3. 他一入门就闻到了厨房传来的香味。

   tā yī rù​mén jiù wén​dào le chú​fáng chuán​lái de xiāng​wèi.

   As soon as he entered the house, he smelled the fragrance coming from the kitchen.

   Source: Dong Chinese Dictionary