Help needed in socializing and bonding with human

The main goal when bonding is to have your rats associate you with positive things. If they are uncomfortable with handling then take a step back, sit by the door of the cage with treats and allow them to come to you on their own terms. Wait until they are super confident in your presence before conditioning them to your touch.

Here are some things you can do:

• Throw treats into the cage as you pass it
• Put some kind of cloth that smell like you into the enclosure
• Sit by the cage and talk to them
• Reward them when they seem curious about you
• Give them a licking treat on your hand to force them to stay in close proximity to you
• Give them tiny bits of treats to have them continuously come back for more

If your rats are comfortable in your presence, you can do the following to condition them to your touch:

• Allow them to come to you then reward
• Touch gently then reward
• Once they are unafraid of the touch then stroke then reward
• etc.

Once they are comfortable with handling:

• Take them to a bathroom or bed
• Make sure there are no hiding places besides for a hoodie or blanket on you
• Allow them to explore

For the first day or two, sit by their cage and just talk to them. Put your hand flat in the cage and don't move it, let the rats crawl onto your hand and sniff it. (it'll be uncomfortable but it's worth it to have socialized ratties! )
If they bite you, move your hand away and make an "eep!" sound. That's what rats do when something hurts, and if the rats aren't intending to bite you hard then they should understand.

You can also dip your finger in some baby food (meat baby food is preferred among most rats) or plain yogurt and let them lick it off your finger. Unlike solid treats, they won't be able to run off with it and instead will be forced to eat by you. If they bite, get a metal spoon and offer the liquid treat on that- this will teach them to lick instead of biting.
Every time you pass by the cage give them a treat. Preferably, open up the cage to give the treat as they could starting nipping fingers if you give them treats through the bars.

Also, (this is essential for bonding with rats) spend some time with your ratties in a rat-proofed room or a playpen. At first, transport the rats by luring them into a small cardboard box and taking that to the play area. (you can pick them up later on when you've socialized them more) I recommend starting out with a playpen even though rat-proofed rooms will be better later on, since in the playpen you can "customize" the setup to work for you, and it won't be too big. In the playpen, remove everything and sit down with a blanket over you. The blanket is the only hiding spot and the rats should go under the blanket with you since it's dark, cozy, and a hiding spot. Offer them liquid treats. After a while of just sitting there with the ratties, you can start the "touch and treat" method- stroke the rat and reward them with a liquid treat, and repeat until the rat is comfortable being stroked. Practice the "touch and treat" method, and spend time together in the playpen for several days and when the rats seem more confident you can start to pick them up- in the playpen, quickly pick the rat up and put her down, then reward her. Repeat this several times every day until they're used to being petted, picked up, etc.
(Remember it might not come easily to all rats. The key is to spend time with the rats, and you can also repeat and go back to steps listed here!)

Here's a video to make a playpen out of everyday materials, if you need it:

And here are videos on socializing rats/shy rats:

Good luck!