Prioritize bus for RX-PDO

To send PDO messages, a prioritization is done, which message is of high importance, how should we understand this?

In the photo below, the point is that the priority is 181 and then for the rest, where is this set from?

CANopen isn't different from any other CAN bus. The lower the COBID, the higher the priority. 0x180 etc is just default COBID too, you can change to custom ones if you need to change priorities. In fact you have to change COBID somewhere, so that one node's TPDO COBID matches the COBID of at least one RXPDO. It's custom to change the COBID on the part that's easiest to configure, like for example a PLC, rather than changing it for a "dumb" node like some actuator.