The Fluid Grid is the same as a regular Grid, but is used for viewing fluids from the fluid storage.
To insert a fluid, players can SHIFT click or just click in a filled fluid container.
Players can extract the fluid by clicking on it. The Fluid Grid will then fill a bucket with the selected fluid.
Refined Storage will first search an empty bucket in your inventory. If none is found, a bucket will be searched in your storage system.
Some fluids cannot be canned in a bucket, then the only way to extract said fluid is by using an Exporter.