update README.md

README.md

@@ -32,7 +32,42 @@ tsc
 |exampleAuthentication| It contains an example of how authentication is done |[Wiki](https://github.com/alastria/alastria-identity-example/wiki/Authentication-example)
 |keystores| Contains the mocked keystores that we used to create the identities with different roles. These roles are explained [here](/keystores/README.md) |
 
+## Environment requirements
 
+**This section specifies the environment requirements for the successful execution of the examples.**
+
+First of all, to avoid possible errors with node and npm, it is recommended that the installation is done through **Nvm**.
+
+Once you have **Nvm installed**, all you need to do is install the required version of node with .
+```sh
+nvm install <version>
+```
+
+On the other hand, if any problem persists, it is recommended to **clean the npm cache** with the following command 
+```sh
+npm cache clean -f
+```
+
+The list of Npm and Node versions that have worked for the different members of the core identity team are listed below.
+|**Versions**|**Does it work?**|
+|:--|:--|
+|Node 14.19.0 && Npm 6.14.16|**OK**|
+|Node 14.20 && Npm 6.14.17|**OK**|
+|Node 14.20.1 && Npm 6.14.17|**OK**|
+|Node 16.13.0 && Npm 8.15.0|**OK**|
+|Node 16.13.2 && Npm 8.1.2|**OK**|
+|Node 16.14 && Npm 8.3.1|**OK**|
+|Node 18.19.0 && Npm 10.2.3|**OK**|
+
+### Problems with the version of the library and the json-objects installed when running npm install
+If you encounter problems with the version of the library and the json-objects that are installed after npm install, you need to perform the following steps to solve these problems:
+- Delete node_modules folder -> `rm -rf node_modules`
+- Delete the package-lock.json -> `rm package-lock.json`
+- Clean the cache -> `npm cache clean -f`
+- Install all dependencies -> `npm install` (from the root directory)
+
+Following these steps then check that the version of the library and the json objects that have been installed are correct. To do this go to the `node_modules -> alastria-identity-lib` folder and look at the code inside, to check if it is the one you want.
+Perform the same checking operation for the json-object code `node_modules -> alastria-identity-json-objects` 
 
 ## How to use it