On the site ofis a TextUml tutorial.
Also the famous Pet Store is modelled in textUml.
What is missing as of now in TextUml is
saving real constants (only integer constants so far)
creating list/array constants
If you want to use closures or predefined datatypes and stereotypes you may have to download the source of the project. Otherwise some files used may be missing. In some examples for instance base.tuml is imported.