如何从LinkedIn oAuth2读取accessToken

I am new to linked in oAuth 2.0 sorry to ask this simple question.

my application developing in react js and the backend is in golang.

I am trying to get the access token from LinkedIn oAuth2.0 as per the Visit: http://www.example.com/)(https://docs.microsoft.com/en-gb/linkedin/shared/authentication/authorization-code-flow?context=linkedin/consumer/context

in step 3 I can able to get the accessToken like this.

{
"access_token": "AQWAyxU2xC-2-MZILNex2q_EOKUsrar1GB3l-o1Cm3ErUcfjpe3Ri4QQzCgpMywYG7r-sSdLQPjTcJXUNDufaz97Xr9TtG8OOGl2ayCj7iwEbtRWojBkqkPeCXg-MjwX-AN6rgMzOnl4BIRp5r9xJrwQ0M7v6nyCZojLKXtSaVtomKF4cLyXurRPFOK_MutgYAb7gisaAloH4IjEOfmbab_O-MP-asDCvm6xuO6tEcf9Ws3HCsW5qGm_WYOZYIYGZKQeXps24zksj0X3M-fG1Ahb3_Z6KK5OScKtzOjyQmv3lBxNmgzoqLXc3TKwEeO4ZHmvYLlnBprbgE0eBt_moAVzHoybRg",
"expires_in": 5184000
}

But my problem is how I can read this token for later uses because it's redirecting to the LinkedIn page from there I am unable to get it and I am unable to use the rest API because of CORS issue.

I come to know finally that we have to use cURL to read the accessToken from http ex: in node js we can use npm curl-request