First step please create new file by name

vim ~/.zshrc

Then put the code below

# Path to your oh-my-zsh installation
export ZSH=$HOME/.oh-my-zsh

# Look in ~/.oh-my-zsh/themes/
ZSH_THEME="robbyrussell"

# Theme settings
export TERM="xterm-256color"
SPACESHIP_TIME_SHOW=true
SPACESHIP_EXEC_TIME_SHOW=true

HIST_STAMPS="yyyy-mm-dd"

# Which plugins would you like to load? (plugins can be found in ~/.oh-my-zsh/plugins/*)