Hydrogen Isotopes available?

Hello I have been using the older version of Avogadro for years and just now found out about Avogadro2, so please forgive me if this is an obvious questions. I am trying to build a molecule that contains Deuterium and Tritium, is there any way to do that in Avogadro. I know the bond distance would be different due to the use of the isotopes and I want to make sure my geometry is correct before I continue with my computational calculations. Any advice would be helpful.
I really just need the cartesian coordinates, I can continue on from there.

Technical information:
OS: MacOS 14
Avogadro2 version: 1.99

As far as I know, any isotope specification is done with the program you are trying to do your computations in. For example, ORCA will let you specify if an atom is an isotope in their input files, but this is not something that Avogadro supports. I would recommend checking the manual for whatever program you are using to do your real computations.