DesignScript Libraries

When using DesignScript, what libraries are loaded by default and how can, or can we load other libraries in DesignScript?
I am looking at the folders:
(C:\Program Files\Dynamo\Dynamo Core\1.3)
and
(C:\Program Files\Dynamo\Dynamo Revit\1.3\Revit_2018)
I am looking at DSOffice.dll with Visual Studio and wondering if I can access any of this library methods with DesignScript?

I am not a programmer so I know very little but I feel if I knew what I could load, what is already loaded and what I can access would help me understand more about DS.

Thanks

AlanC.

A quick search in the forum yielded some interesting results, like this one:

Hi ArchitetCoding,

Thanks for the reply, yes, I did do a search in the forum before posting, and I found the same site you posted a link to. Only that two out of the three links no longer work “404 Page Not Found” and the PDF which I have mostly read doesn’t say anything I can find about dll libraries that I am asking about in my original post. And the Revit Wrapper is python not DS, so if I missed this information, I am asking for assistance and have someone just explain it to me, because after my search results and reading I am still having trouble.

Edit
I found some information in the PDF after another look and is says I can import C# assemblies but only with .DS extensions then this can be imported into Dynamo. I have done no search on this as of yet, which I will but can you tell me how this works? 7.2 of the DesignScriptGuide.

Thanks for any assistance

AlanC.

Following up, I found some information, on the bottom of page 2

File → Import Library

 It is important to note that the DesignScript language is independent of Dynamo. For example, Dynamo also implements a number of useful
geometric and domain specific functions which can be programmed using DesignScript. We will use examples of these geometric classes and
methods to illustrate the features of the DesignScript language. However, it should be noted that these classes and methods are not part of
the DesignScript language. Other libraries, including geometry libraries can be built using C# development tools operating within the ‘Zero
Touch’ conventions, and the resulting DLL’s can be loaded into Dynamo using the ‘file/import’ command and accessed via the Dynamo UI and
DesignScript.

 There are some aspects of DesignScript which are currently not supported through the Dynamo User Interface, but these can be accessed by
using a regular text editor to create a DesignScript source file [with the .ds extension]. These files can also be loaded using the Dynamo
‘file/import’ command.