I've done this on countless American cars, but would appreciate any tips/help/how-tos for a 98 Civic.

Thanks

 

Is it manual or automatic?

 

Automatic.
Thanks

 

I'm getting ready to do mine. My haynes manual say to warm up the fluid by driving, drain it from the plug, replace the plug, then add 1/3 of what you drained. Than turn the car on, and add half pint at a time through the dipstick hole until it is at the right level. My manual is for 01-04 MY though. A car as old as yours probably needs to be flushed though, since you've probably exceeded the life of the fluid. To flush, change it twice in a week.