Update README.md

doc/testing/postman/README.md

 # Postman
-In this section we can use Postman to publish an API as a provider and use it as an invoker.
+
+This section shows how OpenCAPIF is used through requests made with Postman, from the creation of a provider together with the publication of an api, to the creation of an invoker and the consumption of the published api. Everything you need to run the test is in Postman-Test.zip.
 
 ## Requisites
 
@@ -14,7 +15,7 @@ In this section we can use Postman to publish an API as a provider and use it as
 npm i
 ```
 
-1. Run the <a href="./script.js" download>script.js</a> with the following command:
+2. Run the <a href="./script.js" download>script.js</a> with the following command:
 
 ```
 node script.js
@@ -22,6 +23,11 @@ node script.js
 
 3. Import Postman collection and environment variables (<a href="./CAPIF.postman_collection.json" download>CAPIF.postman_collection.json</a> and <a href="./CAPIF.postman_environment.json" download>CAPIF.postman_environment.json</a>)
 4. Select CAPIF Environment before start testing.
+5. Install the necessary dependencies from requirements.txt using the following command:
+
+```
+pip install -r requirements.txt
+```
 
 ## Remote CAPIF