You can see the most up-to-date documentation for the commandline in Skyline using the menu item "Help > Documentation > Command Line".
The commandline argument to import peak boundaries is:
--import-peak-boundaries
To import analyte concentration, the commandline argument is:
--import-annotations
If you want to learn what the format is for the import annotations file, you can use the menu item in Skyline:
File > Export > Annotations
That menu item shows you the complete list of properties and annotations that Skyline can both export and import. If you look at the CSV file that it generates you will see how to refer to the replicate, and what to name the column which contains the concentration value.
By the way, if you happen to have named your raw files so that the concentration is part of the filename, there's a feature where you can tell Skyline how to extract information from the filename and put them in properties or annotations. The way to get to that feature is:
Settings > Document Settings > Result Files
Here is the page with information about how to use the Result File Rules feature:
https://skyline.ms/wiki/home/software/Skyline/page.view?name=ResultFileRules
-- Nick