How to add days/weeks to a Hire date token in Alert Composer template and Message section?

We have a requirement where a notification(mail) to be triggered to Line Manager with details about the worker email, hire date, Date to be calculated based on 8 weeks after the hire date, Date to be calculated based on 16 weeks after the hire date, Date to be calculated based on 24 weeks after the hire date used for probation review dates for Line manager.

Currently Used tokens in the Message section:

${AlertUtils.toString(AlertUtils.empManagerList(workers.PersonId).WorkEmail)}

${AlertUtils.person(workers.PersonId).WorkEmail}

${AlertUtils.formatDate(workers.workRelationships.StartDate,'dd/MM/yyyy')} fetching Hire date

Not working:

${workers.workRelationships.assignments.JobName} this is not fetching job name. Instead giving null value