First of all, the main usage of tetr is to produce the SIESTA input <job>.fdf file as described in Section 2.6. Here <job> is the name of the SIESTA job. tetr can process both <job>.fdf and <job>.XV files.
The DOS option is not yet supported for SIESTA since
it is not possible at present to choose at will the -points
for the SIESTA run. The situation may change in the
future, or, as a user, you may do the appropriate changes in SIESTA
yourself. In those cases little modifications are required to allow
for the DOS/LDOS support, similar to the VASP case
(Section 4).
Finally, the calculation of phonon frequencies with SIESTA is completely supported. tetr will take care of all input and output files as described in Section 2.6.8. No need for lev00 in this case at all!