I just figured it out:
1. "through your employer" normally means those that contribute through your payroll which is pre-tax money. And it normally reports on your W-2 Box 12 W, it has already been deducted from your taxable income.
2. "you personally made" is the part you contribute using your after-tax money, which needs to be deducted from your taxable income, and this part can further lower your tax.
