Pay Stubs, Deductions & Saving for Retirement

i have learned that  when u pay your retirment plan you have a fixed percent that u have to pay i pay a 10% fixed payrate. another thing that i learned that on a pay stub there is two diffrent rates of mony income gross pay and net pay. another thing that i learned is that u can  get a deductible for some of the taxes or mandoatory things u must pay so it can be a b it easier to pay and can help u out in the log run.