1. installing psql

// this command should create 'postgres' user.
`sudo apt install postgresql postgresql-contrib`

// postgres is like a superuser for the database

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2. accessing postgresql command interface

// this will login as postgres
// after entering your normal password for sudo
`sudo su - postgres`

// then accessing postgresql command interface as following
`psql`

// now psql shell should be running

// this command will print the full command list available
`\help`

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3. creating a dummy user (for server-side connection (from php))
// you can change any of this username(`foo`) or password(`bar`)
`CREATE USER foo WITH PASSWORD 'bar';`

// it works in lower litter too
`create user foo with password 'bar';`

// verifying user been created by
`\du`

// now we just need to give `foo` a full access
`alter user foo with superuser;`

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4. creating a database to store our tables in it
`create database chicken_fight`

// verifying database been created by
`\du`

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5. now we done we can continue from php i think
// to exit the database
`\q`

// to return to regular user mode, and logout form postgres
`exit`