A short instruction as PDF file.

Important note: The part with the upgrade process to Joomla 4 only serves to illustrate the jDownloads upgrade and is not intended as a general Joomla upgrade guide. For this, many more things have to be taken into account. You can find comprehensive instructions for this here, for example: https://docs.joomla.org/Joomla_3.x_to_4.x_Step_by_Step_Migration