I am making a scatterplot graph in SPSS. It has to label participant IDs on the X axis and their difference scores on the Y axis.

I am making a scatterplot graph in SPSS. It has to label participant IDs on the X axis and their difference scores on the Y axis. I cannot - CAN NOT - get the thing to label the X axis in increments of 1 (or, i other words, to list each participant's ID).