Follow this guide to install Dynatrace OneAgent for the very first time.
Once you've followed this guide, you'll have OneAgent installed onto a host and can use Dynatrace to monitor that host and its processes.
This guide assumes that you have:
To download and install OneAgent on a host:
Go to Deploy Dynatrace.
Select Start installation. Then Select your platform where you want to install OneAgent.

Paste your PaaS token in the Download token field or select Create token to generate a new Deployment API token.
Copy the token and save it somewhere safe, because you will not be able to access it again.
Enter or select the appropriate parameters

Download OneAgent. Either use the provided CLI command or select Download.
Verify the signature. Use the provided CLI command. (Note: Linux and AIX only.)
Install OneAgent. Either use the provided CLI command or run the executable by selecting it in the GUI. Follow the steps as described in the installer.
If you install via the GUI, you should add the following options in the Optional: advanced command-line settings screen:
--set-monitoring-mode=fullstack --set-app-log-content-access=true
When the installer shows a Congratulations! Dynatrace OneAgent was successfully installed! message, OneAgent is installed on the host. Select Finish to exit the installer.
Because OneAgent can't inject itself into running processes, you'll need to restart all processes that you want OneAgent to monitor.
To confirm that OneAgent is monitoring your host, open Dynatrace and go to Infrastructure & Operations > Host. If everything is working as expected, you'll see the name of your host in the Hosts table. See the screenshot below for an example.
OneAgent is now set up and monitoring your host. See Get started with Dynatrace Managed to continue your first journey with Dynatrace.