At job related expenses I read union dues, so I input my unoin dues amount for 2016, then I read about a 2% rule, please explain?

Union dues are considered an employee expense, which is deductible on Schedule A.  You will only get the benefit if:

• You itemize your deductions (Schedule A); AND
• All of your unreimbursed employee business expenses and other miscellaneous itemized deductions added together are more than 2% of your AGI.  [Only the amount over 2% AGI is deductible.]