This is the AutoHotkey script I use to type common special characters, including Spanish accented letters, superscripts, math and science symbols. I've also included shortcuts to simulate the media control keys.
You can copy and paste the script, or download a precompiled version that doesn't require AutoHotkey to run.
This is written in AutoHotkey 2.0 syntax. '!' means Alt, '+' means Shift, '^' means Control, so '!a' means pressing 'Alt' and 'A' together.
Put the .exe (or a shortcut to it) in %appdata%\Microsoft\Windows\Start Menu\Programs\Startup. You can jump to this folder quickly by presing Ctrl+R and running shell:startup.
You can edit this AHK file using any text/code editor, such as Visual Studio Code with the "AutoHotkey v2 Language Support" extension.
Then, you can compile it into an exe file using Ahk2Exe. Select "C:\Program Files\AutoHotkey\v2\AutoHotkey64.exe" as the Base File, since this script is in AHK v2 syntax.
I've included the ICO icon file in the repo. You can specify the icon in Ahk2Exe.