This is the easiest method.
Steps (for Chrome)
Click and hold the tab at the top (where the page name is).
Drag it downward.
Release the mouse button.
The tab will become a separate window.
Right-click the tab.
Click “Open in new window.”
For Windows
Click the window you want to arrange.
On your keyboard, press:
Windowsキー + ←
Snap it to the left.
On the other window, press:
Windowsキー + →
Snap it to the right.
The two windows will now be displayed side by side.
Press Ctrl + N to open a new window.
Display a different page in each window.
Arrange them side by side using the method above.