The experiment-wide compensation will be used for gating in the Gating Editor. You can find more about the experiment-wide compensation in this article here.
To change the compensation, click on the edit pen under the Active Compensation in the Gating Editor.
If your files are not compensated and you need to create a compensation matrix, click on the Compensation tab on the right side of the experiment level navigation bar.
From there, you have the option to manually create a compensation, import an existing compensation matrix, or automatically create a compensation matrix from single stain controls.