You simply enter the SSA 1099 just like you ordinarily would, with the amount withheld entered in Box 6. Unless you had no other income, some of your social security may be taxable, so there's no reason to expect a full refund of your withholdings. See the following link about the taxability of your benefits:
https://faq.ssa.gov/link/portal/34011/34019/article/3831/must-i-pay-taxes-on-social-security-benefit...
