AWS secrets manager documentation help

Ok, thanks. but where do I run it and how? can you please help me?

For example, if you are running an application on Amazon Linux 2023 EC2, you can install it as follows. Please connect to EC2 using SSH etc. and execute the following commands.

sudo su -

# Run it if you haven't installed git on EC2.
sudo dnf install git -y

# Please clone from the Secrets Manager Agent repository.
sudo git clone https://github.com/aws/aws-secretsmanager-agent.git
cd aws-secretsmanager-agent/
sudo dnf -y groupinstall "Development Tools"
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
. "$HOME/.cargo/env"
cargo build --release

# You can confirm that a file called "aws_secretsmanager_agent" has been created.
ls target/release/ -l

mv target/release/aws_secretsmanager_agent aws_secretsmanager_agent/configuration/aws_secretsmanager_agent
cd aws_secretsmanager_agent/configuration/
bash install

I run my server in elastic beanstalk which manages EC2 instances, is this possible there?

It can also be used with ElasitcBeanstalk's EC2, but since ElasitcBeanstalk's EC2 is supposed to be managed by AutoScaling, you need to run the installation command on the EC2 you want to use as the AMI used by AutoScaling. https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/using-features.managing.as.html
You can create a custom AMI by following the steps in the document below. https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/using-features.customenv.html