The second type of errors is linked to difficulties in understanding the commands labeled as operating errors. Users often mixed up the "move" command, which was operated with the thumb, with the "select" command, which was a triggered operated with the index finger. The activity chronograms (Figure ) shows that this type of confusion is very common at the start of use. They also appeared when the user is hindered by malfunctions (the third type of error). Results show that operating errors are linked to the ease of learning how to use Simubat 4.0 Gen-2. Despite the difficulties and confusion associated with the commands, we found that the participants were able to use the application quickly and correctly, indicating that it was easy to use. As in the study written by Criollo et al., we can therefore identify this type of behavior as being linked to getting to know the tool. Regarding the qualitative content analysis and the CSUQ score, there were no technical drawbacks significant enough to reduce participants' enthusiasm .