Edit an asset
Once imported, select the asset and click on the button Edit Selected Asset in the NPanel.
To show the Fluent Catalyst menu, click in the viewport.
About The Menu
To quit the Fluent mode, you can either Right-Click or click on 
Each button is a setting you can adjust on the asset, the number and the name of settings will be different for each asset.
Adjustment
To adjust a setting click on the corresponding button. This will enter the Adjustment mode and by Moving your mouse Left and Right it will change the value of the setting.
Once you reached the setting you want, Left-Click and click on Validate
Adjustment Precision
If the setting is going too fast, Hold SHIFT while Moving your mouse. If the setting is going too slow, Hold CTRL instead.
Precise adjustment
Once in Adjustment mode, you can Hold SHIFT, type the value on the NUM Pad and press Enter to validate.