Changing kibana logo?

Elastic Stack Kibana
1

Hi,
can somebody help me to change kibana logo please?

I am using 6.2.3. I tried many discussions about same, but every case is different and I am not finding those directories or files on mentioned locations. May be the version differences in every discussion.

Br,
Sunil.

2

Also please change me what should be the size of the logo?

3

Where you successful in changing the logo?