New degus will be scared of you. By putting your hand into their cage (their 'safe' home) and backing them into a corner you are acting like a predator and they will try to escape. Repeatedly doing this will cause them to become afraid of your hand and you. So don't do it!
Instead, let your degus come out on their own. Let them explore. Let them sniff you. If a degu approaches you on their own, reward them with a treat. You will quickly see that this results in your degu choosing to come up to you more, and the others will learn that coming up to you means good (not bad) things happen to them.
Degus regard getting food as a very good thing, which is why you are able to train them. It's known as positive reward feedback.
Once your degus have learnt to approach you, stop rewarding them for doing so. Instead, only reward them when they put their forepaws on your open hand. Soon they will all be doing this.
Next, stop rewarding for this and instead only reward them when they climb onto your hand fully. Of course you must give them the food and let them jump off your hand if they choose to or you could scare them and undo all your hard work. You can encourage your degus to climb onto your open hand by sprinkling a line of porridge oats up your hand and arm. Let them eat the oats and get off when they want to, or you could make them afraid of becoming 'trapped' on your hands.
Once your degus are comfortable with walking on your hands and arms, you can pick them up. Let them jump on your hand, pick them up (be sure to keep your hands flat and open), let them walk around your arms for a while and then put them down, then reward them straight away.
After a few weeks training, your degus will love being picked up.
Remember that degus hate being held around the middle, or restrained like this, as in the wild this is how a predator would grab them. If you do this, your degus will wriggle wildly to get free (this would help them escape a predator) and you will destroy any trust your degu has built up in you so far.