Sounds like two servo plugs are in the wrong slots and one of them is upside down.

The elevator does nothing because that plug is upside down.
The throttle stick is moving the elevator servo because the elevator servo plug is in the throttle slot on the RX.

Beginners, there are some simple ways to beat this Futaba problem. It is actually a problem with all RXs that label the slots with numbers. Be advised that some brands of radio's label their RXs with names on the slots. An amazingly simple yet very useful thing to do for beginners and experts alike. Anyway.......

Learn what the numbers mean and write it on something and stick it on your TX. You might also stick it into the airplane. And on the wall of your shop. Or just memorize them. And remember that the numbers mean different things by brand (of those brands that don't feel like printing names instead of numbers that is). Or if you're a beginner, consider starting out with a brand that puts names on things.

So how to keep from mixing up the plugs...............
Start from the servo. Figure out what it drives first. Keeping that in mind, trace the servo wire to it's plug. Now you know what the plug does and what RX slot it should go in. Look at the slot names and plug it in. If it doesn't want to go in easily, there is a reason. The plugs either have tabs (A good Futaba idea as they have tabs to keep you from using them on other brands of RXs and to keep you from plugging the plug in upside down) or a shape that matches the plug hole. If you have a Futaba servo look at the plug and you'll see the very prominent tab. Any other brand, don't rely on it's shape, simply plug it in the easy way and see if the servo works. If it doesn't then unplug, turn over and plug back in. After plugging in the first one, plug all the rest into their correct plug slots with the three servo wire colors matching the wire colors on the first plug.

It's often a good idea when you're installing servos to write on the wood somewhere around that servo what it does. Like "rudder" beside the rudder servo. Of course, if you've got a Futaba radio, you might want to write whatever number means rudder. And then maybe write rudder also.