QtplasmaC- actualization error

I have a 3 axis-machine with a mesa 5i25+7i77+7i78. We also have a Hypertherm Powermax45. We bought two THCAD5 one for the THC and the other one for ohmic sensing. I have two issues. One the one hand, I tried to use PlasmaC and it does not work. I am a beginner in electronics so, I might be asking something stupid, sorry about that. I'd like to know if have to update the firmware to use the THCAD5? Moreover, I found out that I should use QtPlamaC instead of PlasmaC. Nonetheless, I am not sure how to install it, I could only find how to update it by writing this on the terminal:

Thank you very much for the guide! If I already have Linux and LinuxCNC installed, can I just start from the step 7? Or I have to reinstall Linux and LinuxCNC to be able to use QtplasmaC? Now I am using debian GNU/Linux 9 and my LinuxCNC version is 2.8.2

First of all, thank you very much. I might need to create a new thread for this, not sure.
I wondered how can I use the QtplasmaC because my program does not work. However, I believe I might have a different problem. I have not upgraded yet my LinuxCNC. If it is needed to run the program I'll delete my current version and follow Snowgoer steps to install the 2.9 version. I have one Mesa THCAD5 card for the THC wired on the encoder 3 A of the mesa 7i77 and another THCAD5 for ohmic sensing wired to the encoder 4 B.When I run the program the attached error message pops up. I have also attached the ini and hal files. May you help me find the problem, please?

Missing sserial I/O usually indicates a power problem

Does the 7I77 have both 5V and field power connected?

I think so.

The red LED from 7i77 circuitboard is turned on which means according to the manual that there is a field I/O fault. However, when I use the 3 axis configuration, without the THCADs it turns green and works well. In both THCAD the CR2 led blinks and the CR5 led glows steadily. Nevertheless, the CR5 led is not green but yellow.

Do you think it is a coding problem, a wiring one, or can be both?

I am still stuck with this. Since I cannot make the program work with Plasmac, I would like to update to LinuxCNC 2.9 to use QtPlasmaC. As I mentioned, I have Debian 9 stretch. I believe that the master branch is only available with Buster, so I'll try to install MX Linux following snowgoer steps.

Just to give you feedback. I managed to install linux 2.9 with QtPlasmaC following snow guide. Thank you for that!
First I downloaded the last version of MX and it does not work with it. It has to be 19.4 like it is said on the slides.