I receive a pension from the state of south carolina and a pension from my previous company that i worked at many years ago. how do I file these on my return?

Pension income is taxable by your state of residence at the time you receive it.  It doesn't matter where you earned it.  If you're an SC resident now, it's all taxable by SC.

Enter each 1099R separately.  The easiest way to get to the 1099-R entry screen is to simply search for 1099-R (upper- or lower-case, with or without the dash) in your TurboTax program and then click the "Jump to" link in the search results.

Enter a 1099R under
Federal Taxes on the left side
Wages & Income at the top

Then scroll way down to Retirement Plans and Social Security,
Then IRA, 401(k), Pension Plans (1099R) - click Start or Revisit

If you are filing a Joint return be sure to pick which person it is for.

certain states like Illinois don't tax retirement benefits and TT automatically deducts them on state return.  

SC taxes retirement income but allows a $15,000 exemption if you're 65 or older.  SC does not tax Social Security benefits.