Click on the beginning of the content you want to copy, then drag the cursor to the other end to highlight the text that you want to copy. This launches the context menu.  To right-click on the touchpad, either hold the Alt button and then click on the touchpad (Alt + click) or tap the touchpad with two fingers at the same time. If you have a mouse connected to your Chromebook, click the right-hand button on the mouse instead to launch the context menu. It's a selection near the top of the context menu. Navigate to the place or the document in which you want to insert the content. This launches the context menu.  To right-click on the touchpad, either hold the Alt button and then click on the touchpad (Alt + click) or tap the touchpad with two fingers at the same time. If you have a mouse connected to your Chromebook, click the right-hand button on the mouse instead to launch the context menu. It's a selection near the top of the context menu. Doing so inserts the copied content into your selected location.

TL;DR in Vietnamese:
Bôi đen nội dung. Nhấp chuột phải vào nội dung. Nhấp vào tùy chọn Copy (Sao chép) nằm gần đầu menu. Đi đến nơi mà bạn muốn chèn nội dung. Nhấp chuột phải tại vị trí cần chèn. Nhấp vào tác vụ Paste (Dán) nằm gần đầu menu.