David,

Changing the oil in an automatic transmission is not a difficult job, though it's messy.

However, since you asked if there's a filter, and where you put the oil in, I suspect that you should leave this job alone.

If you are determined to go ahead and do it, buy a manual, read it, and follow the instructions. Better still, get someone who has done it or is well versed in the job to do it with you. That way you will learn and it will be done correctly. Otherwise you are quite likely to find yourself with a remarkable mess and an undrivable truck.