Itemusage spacethe other information
hide if only have one value,or show according to the customfield of issueworkflow-conditionyou can spicail the  specify  customfield(multiuserpicker,or multiselect)
show if no value,or hide according to the customfield of issueworkflow-condition 
show if only have one value,or hide according to the customfield of issueworkflow-condition 
true when the all subtaks have done,or false workflow-Validator 
true when the associated issue types and states are same as settings,or falseworkflow-Validator 

true when the all subtaks have done,or false

workflow-Validator 

make the assigneer of this issue to watch this issue   

workflow-postfunction 
make the customfield(single users) of issue to become the assignee of issueworkflow-postfunction 

make the value of the customfield(single user) to watch this issue

workflow-postfunction 

move current user to this issue the customfield(multiple users)

workflow-postfunction 

move the assignee of issue to the customfield(single users)

workflow-postfunction 

move the current user to the customfield(single users) of issue

workflow-postfunction 
remove current user from this issue the customfield(multiple users)workflow-postfunction