The OSC Send Action lets you declare an OSC address, the arguments to give that address, and the OSC device you are sending to. When entering values for the second field, make sure you use commas to seperate each argument, and make sure to format the data as the value its intended to be. For example, if you are trying to send a string, make sure you put "" around it. The third field is a dropdown that lets you select ONLY OSC devices from the Device tab.