add(p2p/foundry): explain more the setup

p2p/3.foundry/SETUP.md

@@ -1,17 +1,31 @@
 # Setup - Foundry
 
-## Install foundry
+- Open your terminal and type
 
-Please follow the instructions given [here](https://book.getfoundry.sh/getting-started/installation).
+```bash
+curl -L https://foundry.paradigm.xyz | bash
+```
+
+This will download foundryup.
+
+- Then, you can download foundry by running `foundryup`
+- If everything went fine you should be able to use `forge`, `anvil`, `chisel` and `cast`.
+- If you are on macos you will need to install `libusb` with
+
+```bash
+brew install libusb
+```
 
 After the installation, run the following command to ensure it has been properly installed on your computer:
 
-```shell
+```bash
 forge --version
 ```
 
 It should print your current version.
 
+If you have some troubles during the installation, you can refer to the [official documentation](https://book.getfoundry.sh/getting-started/installation).
+
 ## Initialize your project
 
 Now we will initialize the project: