Shell script for requesting a boss OIDC access token

boss-access-token.sh

#!/bin/bash
BOSS_TOKEN_URL="https://auth.theboss.io/auth/realms/BOSS/protocol/openid-connect/token"

echo -n "BOSS Username: "
read BOSS_USER
echo -n "BOSS Password: "
read -s BOSS_PASSWORD
echo -en "\nBOSS Client Id: "
read BOSS_CLIENT_ID

RESULT=$(curl -s $BOSS_TOKEN_URL \
    -X POST \
    -H "Content-Type: application/x-www-form-urlencoded" \
    -d "username=$BOSS_USER" \
    -d "password=$BOSS_PASSWORD" \
    -d 'grant_type=password' \
    -d "client_id=$BOSS_CLIENT_ID" 2>/dev/null)
TOKEN=$(echo $RESULT | sed 's/.*access_token":"//g' | sed 's/".*//g')

echo -e "\n"
echo "Your authorization token is (copy the entire line):"
echo
echo "bearer $TOKEN"

Hi,
Greetings!
I have onboarded my app on OIDC, and i have a client ID, client secret, i'm going on with a Auth Code flow.
Currently in my application i have eliminated the cookie related code, please suggest how do relying party will validates the ID_TOKEN and retrieves the end user.