Not clear with question? You want to use it in EP or inactive one to make active?
If you want to put in EP then you need to add it to a subject area and then added it to EP.
Uncheck inactive to make active.
OOTB Mappings can't be edited. To make changes to copy the container into a new container in DAC. Changes can be done on the copied Container. After that make changes to the execution plan with the copy container.