We recommend installing Fiji, which is a distribution of ImageJ which includes many useful plugins.
You can find instructions on how to install Fiji on your machine here.
Further information on plugins and their installation can be found here.
Instructions on how to install Napari can be found at this link.
You can install Python 3 on your machine with Anaconda, a free and easy-to-install Python distribution and a collection of open-source packages, which includes a package and environment manager.
Detailed installation instructions for various operating systems can be found on The Carpentries website and in the Anaconda documentation.
MATLAB is a licensed software by MathWorks. Please contact your Institution to verify if you have access to a license. If this is the case, you can find detailed instructions on how to install the software here.
Alternatively, GNU Octave is a free and open-source alternative to MATLAB which shares its syntax (more about compatibility at this link). Installation instructions can be found here.