You can use the "Windows Snap" feature controllable via Win+arrow keys. ↑ for upper corner or maximizing the Window, ← for left side or left Monitor if pressed repeatedly, same for → but on the right side. Press ↑ for the lower corners or minimizing the window.

With this technique you can move and arrange windows faster than dragging and placing them with the mouse.

If you want to arrange windows by right clicking on Taskbar and selecting Show Windows Side by Side.

It will then arrange two Windows side by side as shown in the screenshot below.

somehow I can't get Windows 10 to arrange four windows four by four by selecting Show Windows Side by Side as in Windows 7, but with snap you get the same result although slower.

This works using AutoHotKey. Just close any windows you don't want maximised first, or exclude them using ExcludeTitle or ExcludeText paramaeters. https://autohotkey.com/docs/commands/WinMaximize.htm

!1::
WinGet, MyCount, Count
GroupAdd, AllWindows
Loop, %MyCount%    {
  WinMaximize ahk_group AllWindows
  Send !{tab}
}