Hi Gulaga,
Welcome to the Apple (user-to-user) Community
Re: How can i connect them?
You may need to check that the keyboard is Mac-compatible.
Wondering which MacBook Air model you want the keyboard to connect to:
Eg: For: MacBook Air introduced in 2022 or later, plus MacBook Air (M1, 2020)
How to: Allow accessories to connect to your Mac – Apple Support
___________________________________________________________
In general:
How to: Use Bluetooth devices with Mac – Apple Support
Trouble-shooting:
Wondering whether there's an app you may need to install:
An accessory needs power and to be in "discoverable" mode for a Mac to connect.
If the keyboard has no instructions that came with it:
The best source of help for a product not made by Apple (a third-party product) is the company or person who made it—its vendor or developer:
How to: Contact a third-party vendor - Apple Support
All the best :-)