Well first you need to go right back to basics. Your bird is now scared of hands or becoming that way. Everything that's happening is expected and natural for a new bird so you just have to take it. Sorry but there's no other way. Your bird is nowhere near as bad as some and you must spend a lot fo time just sitting in the same room as your bird. If you just don't because he's not doing what you want you won't get anywhere. If you want the bird to respect you you need to respect it and it's behaviours.
Few things first though:
1. DO NOT put your hand in the cage yet at ALL. Not until you've completed the training.
2. Expect to be bitten- if you don't like bites then there's not a lot you can do because your responsible for this bird now. Bites come with having a bird. DO NOT react to the bite or make ANY sudden movements when bitten. If you get bit its not the bird's fault it's YOURS. There's no such thing as a BAD or MEAN or EVIL bird its the previous owner or you that's made it that way and its up to you to correct.
3. You MUST be patient, this doesn't happen in one or two days, taming and training is a long process.
4. If one step of the training goes wrong lots of times, STOP and return to the previous step and start again.
Translation of Michael's guide: (This is a very basic overview):
1. IF your bird will take a treat from your hand through the bars then start here (if not let me know and I will write on how to get to this stage).
2. You need to use this treat to gain trust with your new bird. Get the bird to eat the treat through the cage bars. Do NOT chase the bird with you hand around the cage, just sit in one place and wait for the bird to take it. Do not react or get excited when this happens, just let the bird do it. You may need to wait for hours on end.
3.Before you start training, do not let your bird have food for 2 hours. Do this at the same time everyday until the bird takes the treat from your hand very quickly and is comfortable with your hand being there.
4.Clicker training- (YOU WILL NEED A CLICKER or you can use a voice command or click your fingers on your other hand) After the bird has been taking treats from your hand for a week or so use the clicker when the bird eats the treat use the clicker or your finger click (on the hand you are NOT holding the treat in). This makes the bird OK with the click noise and associates it with something good. I used a clicker you can get for a dog. It should take 1-3 days for the clicker training but maybe longer. At first click when the bird grabs the treat, then gradually click first, the bird will come to you and then give the treat.
5. When the click sound is linked to something good you can move on. Target or 'touch training' take a small thin stick (a chopstick is useful for this). Put the stick in the cage a about 10cm from the birds beak. DO NOT put your hand in the cage and wait for the bird to touch the stick. When it does take click, withdraw the stick and treat your bird by holding the treat through the cage bars as you remove the stick to distract him NOT in the cage. DO NOT chase your bird with the stick just wait until he touches it.
6. When your bird touches the stick everytime then you are ready to move on. Point the stick left of the bird for a touch, when it touches. Wihtdraw and treat, then move it to the right and repeat the cycle but mix up the order so not left right left right... maybe right right left right left left right right right left. So its not all the same.
7. You can now teach your bird to target where to walk. As your bird now bites hands you will need to teach it to step on a perch first. So put a perch near the open door of the cage and have another one for it to step on outside the cage. Use the same method as before- target it towards the stick and when it climbs onto the stick on to touch it say 'STEP UP'. Again click and treat the bird. You will need to use one hand for this because your other hand will be holding the perch. There is a picture in the original guide how to do this.
8. Once your bird can do this you can then use the same method onto the hand.
Does this make sense?- The first thing you need to do then is get a clicker, get a clean chopstick and your birds favourite treat and start at step one. Don't move on to the next step till you've got it completely.
You see it can be a long process but if you see how tame Michael's and my birds are it is very worth the time. You don't get anywhere without putting the effort in first

Also if you look on youtube there are videos of this which might help the language barrier. Look up Michael, Kili and Truman- bird training or target training etc. You can see what Michael does.