Download the zip archive from the TrueTime homepage. Then
1. Unpack all files to some suitable directory $DIR
2. Start Matlab R2012a or later and cd to $DIR
3. Run init_truetime.m (its in the unpack folder) to add the necessary Matlab paths (cd 'path_address') and to set the
TTKERNEL environment variable.
Issuing the command
from the Matlab prompt will now open the TRUETIME block library,after that you can just unblock it by clicking on the lock icon.