Each operation is different depending on the type of car you drive. Generally, you want to make sure you loosen all of the bolts and connectors under the hood first. Then, get underneath and remove all the connectors and hoses from this angle.
Drain the fluid and remove the drive shafts and axles. Remove the bolts that adhere to the engine housing. Carefully slide the transmission away from the engine to reduce damage to the torque converter and clutch. For a detailed video, watch these instructions on YouTube.