You must have to install node and npm.
curl -fsSL https://deb.nodesource.com/setup_20.x | sudo -E bash -
sudo apt-get install -y nodejs
then install npm install -g @shopify/cli @shopify/theme
Then shopify theme init
you need to install git if not availlable on your system
exit as root and run shopify login
now run shopify theme serve
If it throw error that store not found then run belo command with your store url where you want to login
shopify login --store v.myshopify.com
Again run shopify theme serve
