This isn't a hard job. First, here is a picture of the idler arm. It will help me explaine.
First, remove the cotter pin from the old joint on where it attaches to the drag link. Next, remove the nut holding them together. Using a ball joint spliter, seperate the two bu placing it between the old idler arm and the drag link where they were bolted together. Hit it with a hammar and they will seperate. Next, there are two bolts that are holding the idler arm to the frame. Unbolt them and the part will come off. Reverse the sequence to replace it. Remember, this is a steering component, so make sure everything is tight, and make sure to use the new cotter pin to secure the joint. It doesn't allow the bolt to come loose. Chances are there will be a zerk fitting that will need screwed in to the new part. It just screws in. I think most are around 8mm. That way you can grease the part so it last longer.
As far as the dipstick tube, make sure the o-ring is in place, and put a thin film of trans fluid on it so it slips into place easily without damaging it. I believe the tube bolts to the bell housing of the transmission. You shouldn't have any trouble.
If you do have other questions, let me know. Also, you won't need an alignment after replacing the idler arm. It has no affect on the vehicle's alignment.