okay, go to word, file, page set up, paper (tab), under paper size scroll down to envelope #10 is the standard size, but you should test it first. If you are not using a standard size, select custom then enter the correct dimensions.
then select the margins tab and make sure to change it to landscape, then select ok.
to enter an image or clip art, go to insert, picture, then either choose clip art or if you are using a pic you have saved, select from file.
If you are using a dingbat font, go insert, text box.
then just play with the layout like you did for the passes.
let me know if you get stuck.