This radio is rather a special case. At this time (3 August 2021) there is no support for the GM-30 in the CHIRP software. This makes the task of programming the radio a bit more roundabout, but not particularly difficult. The software for accomplishing these objectives, however, is available only for PCs. 

Jackson Chen has written a very nice blog post on this very subject on the Radioddity website. It covers the two necessary aspects of programming the GM-30:
1. updating the internal program (firmware) in the GM-30, and
2. programming repeater parameters, adding additional frequencies, and renaming the memory locations in the radio.

We have provided a version of the GM-30 data file in the link, below, that will set up the radio for you. The ham channels have frequencies corresponding to the West Contra Costa County frequency table created by Marina Bay Neighbors. Once the radio's firmware has been updated, download this file to your PC, open this file, and use it to program your radio. 

Data file for programming GM-30
(Be sure to do the firmware update before adding this file to your radio.)

Here's a link to a cheat sheet for the memory locations in this radio and the TIDRADIO TD-H5.

Link to a PDF of the recommended menu settings for your GM-30:

GM-30 Recommended Menu Settings (Same for TIDRADIO TD-H5)

NOTE: It has come to our attention that recently purchased GM-30 radios come with a more recent firmware number (6.3.6). The Radioddity website has not yet provided a download for this version. Downloads can be obtained from this page.

Link to GM-30 manual here.