A tutorial that's a little easier to understand.
Okay, let's get started.
First, you need to make your creature file.
Do everything that you normally do to make a creature file, but I would make the tag very simple. In my case, I used "walkdrd" without the quotes. Also, change the Template ResRef to whatever you decide to make the tag.
Under the scripts tab, remove everything, and type the following scripts into their corresponding fields:
(These scripts command the NPC to walk the waypoints you will create next)
Save your .utc with the same name that you used in the tag and Template ResRef.
Now, get the waypoint editor open and enter the following in the Template ResRef, Tag, and Name files:
wp_walkdrd_01 (if you're using a different tag, use wp_tag_01)
Next, put your character in the .git file as normal, and then go to the waypoints section. Click 'Add struct', and then use the following for the fields:
Save the waypoint as what you used in the last step.
Okay, now make however many more that you need, just changing the number on the end (ex: wp_walkdrd_01, wp_walkdrd_02, .etc).
Add the .utc to the .git file as normal, and then go down to the waypoint list and click 'Add Struct.'
Find and existing .git with a waypoint beginning with wp_, and then copy and change the following fields:
Tag: wp_walkdrd_01 (or whatever you saved your waypoint as)
TemplateResRef: wp_walkdrd_10 (or whatever you saved your waypoint as)
XPosition: use whereami cheat to find location
YPosition: use whereami cheat to find location
ZPosition: use whereami cheat to find location
Add more waypoints for a longer path. Once your creature completes the last waypoint, he will return to the first and start over.
Hope that helps, and remember to include your .utc's and .utw's in the ERF!