Remove fill plug, then remove drain plug to let oil out, replace drain plug, pump new gear oil in, replace fill plug. righty tighty lefty loosy... not much to it.
Remove drain plug to let fluid out, replace drain plug and add new fluid through tranny dip stick tube.
If you're going to work on you rig, you need to invest a couple of bucks in a manual. Chiltons can be had for $20, it does a very good job of describing the procedures for most minor maintenance. If you want to go deeper the FSM is around $100. Although the drain and fills above are about as simple as it gets, there are tid-bits of information that I haven't listed which the manuals have (fill height, bolt torques, fluid specs etc..)
Edit: the drain and fills above are for an LX450. You've listed LX470 as your car model, but you posted in the LX450 forum.
I had put down the wrong model. MY car is lx450. Rookie thank you so much for your help.