Hi:
The first place to start is in the demo shown in the screen shot below of a Lesson 5 demo:
Cynthia_sas_0-1686152793089.png
If review the demo or the demo transcript, you'll see how ORIENT= is used with a plot request in PROC FREQ.
Otherwise, look in the PROC FREQ documentation, for the TABLES statement, here: https://go.documentation.sas.com/doc/en/pgmsascdc/9.4_3.5/procstat/procstat_freq_syntax08.htm#procst...
Cynthia