With add variable value actions you can assign values you provide via object flows, to a code snippet of you choise.
You can add them to your diagram by clicking on the Action dropdown → Any Action.
After this select the the Add Variable Value Action in the Action Metaclass toolbox
The name of the add variable action will be used by Embedded Engineer as it is.
Note that the value pin isn't shown by default. To get the value pin, click on the add variable value action and select Value Pin:
In this examle, we use a value specification and its result to write to the variable me->a by forwarding the controlfolw to the next element and also by creating an object flow from result pin to the value pin.
Object flows do not need to run in the same direction as the control flow.