Just as it seems - put the bulb end in the dirt, water in and let it do as it will!

FataMorgana

As far as I know, garlic chives(chinese) have flat leves and produce seeds not bulbits.

It is possible that you have different variety. Or maybe you have planted garlic seeds. Not sure.

Perhaps it is a garlic variety. In looking I did find the variety below that was a garlic rather than garlic chives but it had a "garlic chives" name. Perhaps something like this happened to you. Either way, take it as a bonus. Topsetting alliums are quite prolific. I have a great patch of Egyptian Onions or "walking onions" that started from 1 plant. Plant the bulbs and grow your patch!

FataMorgana

Here is a link that might be useful: Garlic Chives Spears

When can i cut and plant? Do i have to wait for roots to appear? Let it grow bigger?

It's definitely garlic chive. Had it for years. The flowers were white and after the seed pods dried/popped, these onions started growing on top. The stems turned from the dried brown colour back to green. The soil has hardened(like clay), could that be why it's growing bulbils?

There is a simple id rule: Garlic has flat leaves not round tubular.
If its leaves are tubular then it must be some kind of onion or shallot.

This IS garlic chive(Jiu Cai/kau choi, é®è) or whatever you want to call it in English. Look at the picture it has flat leaves. The tubular part is the flower stem.

For best results, plant when it starts to set some roots. Or you can do as happens with my egyptian onions. Carefully bend the flower stalk to the ground so the bulb touches the soil. Fix it there and let it grow and take root while still getting nourishment from the mother plant. After it has taken root and is growing independent of the mother plant, transplant to where you want it to be.

FataMorgana

Thank you. :)