Please readout the 4.4 user guide and the task node attribute description
Assuming the user is named "ayusman" You may set <task mame="myTask" assignee="ayusman" ..> into the process définition.
When "myTask" is reached, the task can be queried among others as "assigned to ayusman" with something like
TaskService.createQuery().assignee("ayusman").list()
Same holds with "candidate" attribute.
Same principle again with "candidate-goups" attributes but this time you have to set a group and membership "ayousman" to it
Regards
jnh