For example, let's say you have a system called "Alpha Centauri" that you want to upgrade. To do so, you would need to access the system view for Alpha Centauri and click on the "System Development" option in the panel on the right-hand side.

Once in the System Development panel, you will see a list of available improvements for the Alpha Centauri system. Let's say you want to upgrade the system's population, which will increase the system's resource output. This improvement requires 250 Food, 250 Industry, and 10 turns.

To start the upgrade, you need 250 Food and 250 Industry resources available in your empire's stockpile. You would then click on the "Develop" button for the population upgrade, and the game would begin to deduct the required resources from your stockpile each turn until the upgrade is completed.

During the 10 turns that the upgrade is being developed, your system will continue to function normally, but you won't see the benefits of the upgrade until it is completed. Once the upgrade is finished, the system's population will increase, and you will see an increase in the amount of Food and Industry generated by the system.

Other examples of system upgrades include increasing the system's defences, unlocking new strategic resources, or upgrading the system's infrastructure. Each upgrade has its own resource and time requirements, and the benefits vary depending on the type of upgrade.

It's important to note that upgrading a system requires a significant investment of resources and time. You should carefully consider which systems to upgrade and when to do so based on your empire's needs and strategic goals.