When you upload activities using the MySports app for phones and mobile devices, file types for manual import like CSV, FIT or TCX are not stored on your computer. Hence it is best to use MySports Connect on your computer if you need those file types for manual uploads.
When you have already uploaded activities using the MySports mobile app, you can copy the ttbin file from iTunes. Then connect your watch to the computer and double-click the .ttbin file for your activity.
Warning: Double-clicking the ttbin file for an activity that was already uploaded using the MySports mobile app will re-upload that activity to the TomTom MySports website, MapMyFitness and RunKeeper. This will duplicate the activity on these sites.
Locating the ttbin files in iTunes
Connect your iOS device to your computer and wait for iTunes to open.
Select your iOS device in the iTunes sidebar.
Select the Apps tab and scroll down to File Sharing.
Select MySports. The ttbin files are listed on the right hand side.
Right-click (Mac: ctrl-click) a file to copy it.
Edit: updated with proofread version