how do you replace the muffler on a cub cadet LT1050??? thank you!!!

Would need the model number off the serial number tag (which is usually under the seat) to look up the assembly. The number will look something like 13WP91AT009, which is a LT1046. This way we will which engine and muffler you are dealing with.

This one is going to be a little involved as with having a v-twin Kohler. It would  a lot easier if you had the single cylinder engine.
 
You are going need to remove the hood first. Don't forget to disconnect the head lamps wiring harness. Then it comes to the fun part.
 
You may need to remove the engine's electric PTO clutch and the drive pulley. This just depends on the type engine to muffler retaining bolts that are installed. This is so you can remove the four engine bolts as you may need to raise the engine once the four muffler/muffler heat shield bolts removed. There are four muffler to engine bolts (maybe hex socket head or torx socket head bolts) that must be removed. Since you need to access these is why the engine must be loose if they are hex or torx socket head bolts. You maybe able to remove these muffler to engine bolt if they are regular hex head bolts provided if there is enough clearance. They are 3/4 long plus the head.
 
Installation is just the reverse of this. But don't forget to torque the PTO electric clutch retaining bolt to 55 ft-lbs or forget make sure the anti-rotation device is in place or you will tear up the electric when you start the engine.