To set a goal for another person you must add an event containing them onto their timeline. This means that you must first create an event type which contains an embedded goal field.
When editing the section of the event type add the field type embedded goal
The edit screen for this embedded goal field has a number of options to allow you to set how you'd like it to work.
I would like only to define predefined goals - Just the goals that you create within this embedded goal field will be assigned to the user when this event is added to their timeline.
I would like only the user to add new custom goals - When this event is added to the user's timeline the person adding it will be able to define the goals.
I would like to define predefined goals AND let the user to add new custom goals - Both the goals that you create within this embedded goal field and any goals that the person adding this event creates will be assigned to the user.
To set goals for someone else you'll need to select either the first or third options. Once you have done this you can move onto specifying the goal(s) which should be created whenever this event is created. First set the goal title which is what the user will see in their overall list of goals. Then optionally provide a description to give the person receiving the goal some extra context.
At this point you have the choice whether to leave the goal open to the user's decision about which events would best demonstrate progress towards it, or alternatively add some specific targets. Setting targets essentially means selecting the specific event types which the user should select from when demonstrating progress. If you specify targets then Kaizen will helpfully suggest all the events of this type as possible options to demonstrate progress when working towards this goal.