Index the converter to the flexplate by laying the converter on its hub, put the flexplate on the back of the converter so the bolt holes in the flexplate lines up with the mounting holes on the converter, this only fits one way. Make a index mark with paint or a marker. This will help you line up the converter to the flexplate before your under the car.
Install torque converter to transmission with some light grease on the converter hub and one pint of AFT in the converter. Make sure converter is fully seated in to the pump.
Make sure both dowel pins are in the block. When transmissions is bolted to the block, check the converter to flexplate clearance, it should be about ¼ inch. The converter should spin freely. Draw the converter up to the flexplate (by hand) and install the converter bolts and line up with the index make you made on the flexplate & torque converter. You may want to add some blue lock-tight to the bolt threads.