Hi Alexander,
this project TRK-KEA_LAB4.zip was made without processor expert support. if we need add pe support, we need convert project to use Processor Expert first.
You can enable processor expert this way:
go to File -> New -> Other -> Processor Expert -> Enable Processor Expert for Existing C Project.
Then refer below manual in help file.

then you can add CAN_LDD as you did.
Have a great day,
Zhang Jun
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------