You'll find sendmaster in your $PS_HOME/sendmaster directory. Here's the quick and dirty guide to how to use it:

1) Edit StartSendMaster.BAT. Add this line near the top of the script to set your PS_HOME (assuming it's not already set, mine never is):

set PS_HOME=c:\apps\pt849

2) Double-click StartSendMaster.bat to launch send master.

3) Put the URL you want to post to in the Server URL. Copy/Paste the XML you want to post to sendmaster in the Input File area. Make sure the headers say what you want (Content-type: text/xml; charset=UTF8), and click Post.

4) Review the responses in the Output Information tab.