I tried to do it myself and got stuck.
You can upgrade to the Live Assist or the Live Full Service.-https://turbotax.intuit.com/personal-taxes/online/#fullservice
See this TurboTax support FAQ for how to upgrade using the online editions - https://ttlc.intuit.com/turbotax-support/en-us/help-article/change-service-level/upgrade-switch-higher-version-turbotax-online/L8sDiPeHV_US_en_US?uid=m9le9ckg