Not able to install flash extensions

I am using Windows 10. I have virtualenv installed. I am completely new to flask and fairly new to programming/web development in general. When installing a flash extension like flask-sqlalchemy are the packages used in flash-sqlalchemy also installed? Or do I have to install each one individually?

For example, after installing sqlalchemy and creating a very basic flask app, based on this tutorial http://ift.tt/2p8iGz5, I got an error:

ModuleNotFoundError: No module named 'MySQLdb'.

I tried to install it and got the following error:

_mysql.c(29): fatal error C1083: Cannot open include file: 'mysql.h': No such file or directory error: command 'C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.11.25503\bin\HostX86\x64\cl.exe' failed with exit status 2

Any help would be greatly appreciated. Thanks.