To add an item with the console giveitem command you need to know the tag of the UTI. After subscribing navigate to the appropriate sub folder in C:\Program Files (x86)\Steam\steamapps\workshop\content\2738630
If you look at the contents you can see which files are UTI files. In this case it is bb_itemsummoner

> To add this item to your NWN2 character you can use the in-game console or purchase it from the Silverwand Magical Emporium.

Could you tell me how please? What item ID does one use?

To add this item to your NWN2 character you can use the in-game console or purchase it from the Silverwand Magical Emporium.

To add an item with the console giveitem command you need to know the tag of the UTI. After subscribing navigate to the appropriate sub folder in C:\Program Files (x86)\Steam\steamapps\workshop\content\2738630
If you look at the contents you can see which files are UTI files. If there is documentation you should read it,

After using the console you may want to reenable achievements by editing your save file globals.xml changing the 1 to 0 (zero) in these lines (credit to Aldroen):
<Booleans>
<Boolean>
<Name>ShowCheatsWarning</Name>
<Value>1</Value>
</Boolean>
<Boolean>
<Name>Cheater</Name>
<Value>1</Value>
</Boolean>
</Booleans>