A property value of a resource can be edited in measure mode. In the bottom panel each property column contains editable cells for each run. Single value edits are automatically saved and that data will appear in black font as shown for the "API Compound" property in the public process "Riffyn PK/Tox Study".
To enter multi-valued data, right click on the cell and enter data using the "editing multi-valued data" interface that appears at the top of the screen. After edits are completed click the "save all" button. Multi-valued data will appear as a yellow table icon as shown in the "Vehicle" property.