I need help about olea bonsai

Hi. First I dont know too much english. Sorry for this and i am new this hobby
Today i bought a new olea bonsai. But tree's trunk is approximately 50 cm. i wanna shorten it.
i am from turkey and the weather is cold in this days.
I will be happy if you are help about this and other care things like it's irrigation, soil etc.

 

Hello, Nisa. You might do a YouTube search for "air layering olive". Air layering is a method of forcing roots to grow in a little packet you make along the trunk. Once the roots grow in the packet, you can cut it off of the old trunk and roots right below the packet, making a new shorter tree.

 

Thank you too much :)