Since you are a nonresident alien you cannot use TurboTax to file your tax return. You have to file Form 1040-NR, which TurboTax does not support.
TurboTax has a partnership with Sprintax to prepare a Form 1040-NR federal tax return and corresponding state tax return for certain categories of nonresident aliens - international students, scholars and non-resident professionals. Go to the link below for the details of who can use Sprintax, and to get started. Contact Sprintax support for help with how to enter your brokerage trades in Sprintax.
Sprintax