Well first off, have you started marker training yet? Without marker training, everything else, including target training, will be completely useless.
Marker training is conditioning the bird to associate a sound with a correct behavior. It's also a promise of a reward. You can watch videos of people clicker training their dogs to understand how it works. It's a noise that marks the EXACT moment a behavior is done correctly. A marker may be a clicker, a whistle, a cluck, or a word such as "yes" or "good". It's my tried and true method of training that I use when training service dogs, training cats, training performance free flighted birds, and I even got to use it to train dolphins during an apprenticeship in college.
Now, marker training only works with a reward. Before anything else happens, you need to figure out what motivates your bird. So your bird isn't motivated by treats? So what? I've used affection as a motivator, I've used toys, and some birds love crunchy crumbly paper or foil. Use whatever motivates your bird.
Now, your first several lessons will start with you building drive for the motivator. Play with it with your bird. Tug usually builds drive with a toy motivated bird. Whatever the motivator is, it must be something that the bird only gets during training sessions (special nut or seed? special toy? scritches in a favorite spot?) and not when the bird is in the cage or casually interacting with you.
After motivation is built, now is when you introduce your marker. Remember, a bird doesn't hear a certain noise and suddenly think "Oh, I like that noise! I think I'll work for it!" Start with just making the marker noise randomly and immediately give the reward. This will take many sessions for the bird to understand that that noise is what makes the reward come.
So now you begin to notice that when you use your marker, your bird is beginning to anticipate the reward. Now is when you start your target training. Introduce your target to the bird once again. I'd actually start while your bird is in the cage, with the door open. Your bird may automatically touch the target, or it may not. If it doesn't (which is quite normal), I would reward any interaction with the target what so ever. Your bird looks at the target. Mark and reward. Your bird leans in. Mark and reward. Your bird takes a step towards it (even accidentally), mark and reward. Eventually the bird will figure out that the interaction with the target is what is making the reward come.
Here's a recent picture of me building drive for a toy motivated bird.
And here's target training in action with that same bird.
