Once you receive your final video from Rolla, you can share it straight to Tiktok from directly inside the Rolla app.
Go to the Videos tab
Tap on the project you want to share
Scroll to the asset type you want to share
Tap the "Download & Share" button
Tap "Other"
Scroll through your apps until you find Tiktok. Note that you must have Tiktok downloaded on your phone in able to do this.
Select Tiktok. The app will automatically open with the video loaded in.