I am thinking of having a lawn of green grass. Its a small space 4 by 4 meter. How best to do it?
Welcome to Workshop @rumana. It's great to have you join the community. I'm sure you'll get plenty of great advice from community members about this project, and any others you have planned.
So that the community might assist you better, you might like to add where you are based and what the conditions are like in your yard. For example: Does it get full sunshine? Do you know what type of soil you have? What is currently on that space?
Thanks again for posting and joining the community. Please let me know if you ever need a hand getting the most from the site.
If you're patient, I'd have a go with seed first @rumana. Just go to Bunnings and grab a box and follow the directions. https://www.bunnings.com.au/our-range/garden/gardening/lawn/seeds
You'll just need to decide what type of grass you're looking for. It's particularly important to note how much wear the grass is going to get. That is, will a lot of people and animals walk/run/lie on it? Beforehand I would also turn over the soil and then let it sit for a while. Use a garden fork - easier than a spade. Make sure you get rid of any weeds.
Some good advice here. If you could tell us a little more about your spot, or even take a photo, it would help us give more specific help. Good luck.