How to install marketplace addons?

I want to install marketplace addons (specially rules templates)
I can’t find any information how to do it.
In the addon install screen of main ui only officiall addons appear.

Do I have to change a configuration?
Or are marketplace addons meant to be installed in the filesystem?

Did you enable the marketplace?

Hi, sorry for the late replay.

I reinstalled OH because of other issues and now the marketplace works out of the box.

Does anyone know how to install Marketplace addons via text files?