Note that you use the standard deduction only as an alternative to itemized deductions. Any credits are claimed in addition to the standard deduction, so you should enter anything that's called a credit, even if you use the standard deduction. There are also "above-the-line deductions" that are not itemized deductions and are claimed in addition to the standard deduction. These include the student loan interest deduction and the deduction for IRA contributions. TurboTax does not clearly identify above-the-line deductions. If in doubt, enter it.
The most common itemized deductions, which you don't claim if you use the standard deduction, are medical expenses, state and local income tax, sales tax, or property tax, and charitable contributions. If you know you are going to use the standard deduction, you don't have to enter any of these.
You are posting from the Free Edition which does not support Schedule A which is required for itemized deductions described at the bottom of rjs comment. If you try to enter any itemized deductions, you would be prompted to upgrade to a higher version of TurboTax.
NOTE: See Opus 17 answer for how TurboTax actually handles the entry of itemized deductions in the Free Edition. The above description is not accurate.
Turbotax is designed to ask you about all deductions and then decide for you if it should itemize or use the standard deduction. (This also has the effect of getting people to agree to upgrades that they might not need.) You should be able to skip the itemized deductions. Look for "skip" or "finished" at the bottom of the page listing itemized deductions. You may have to scroll down if it doesn't show right away. Once you indicate you are "finished" with your deductions (even after not entering any), it may nag you a bit ("are you sure you don't own a home/have education expenses/etc") but it should allow you to finish the federal taxes without itemizing.