Yes, you can create a container in Proxmox using an existing template. Here are the steps to do so:
Open the Proxmox web interface and navigate to the Containers page.
Click on the "Create CT" button to start creating a new container.
In the "General" tab, select the "Template" radio button and choose the desired template from the drop-down menu.
In the "Name" field, enter a name for the new container.
In the "Password" field, enter a strong password for the root user of the new container.
Click on the "Storage" tab and select the storage location where the container's files will be stored.
In the "Network" tab, you can configure the network settings for the container, including the IP address and gateway.
Click on the "Confirm" button to create the new container.
Once you have completed these steps, the new container will be created using the selected template. You can further customize the container's settings and install any necessary applications inside the container. Using a template is a convenient way to quickly create new containers with pre-configured settings and installed applications.