Using xfig you will need to make arrows:

1. copy the arrow on the left using the copy button in the panel

2. move its endpoints using the move button near the copy button

3. add vertices using the add point button below the move point button

If you want to move an environment or a procedure

1. use the glue command to glue its components (text, rectangle) into the same component

2. move the big component

When exporting to Postscript set the border margin to 20.