Had a similar question and Arturia Support provided the following details:
To send program changes to the MatrixBrute, it's very simple:
- The MSB (Bank message) will select the line/row of the preset in the Matrix.
- The Program Change message will select column of the preset in the Matrix.
- (The LSB values are not used, and will not be taken in account.)
As an example, sending program change: MSB (Bank) 5 & Program Change 12 will select E12 preset, see attached image.
UPDATED: When counting banks (lines/rows) the first row always starts at 0. So to switch to patch A7, specify MSB 0 and PC 7. And in original example, to switch to E12 use MSB 4 (not 5) and PC 12. Programming values of MSB 5 & PC 12 will result in F12 patch change.