To access the controls of CameraXXL you have to display the Camera Raw dialog. To do that you can open a raw file via File > Open or by dragging and dropping it on the Photoshop Elements window. Non-raw files can be opened in Camera Raw with File > Open in Camera Raw menu command in Photoshop Elements 12 and higher. To do the same in Photoshop Elements 11 you have to choose File > Open As and select "Camera Raw" from the Open As combo box.
You can deactivate CameraXXL, which means that the CameraXXL features will not be available on the Camera Raw dialog. To do that go to File > Automation Tools > CameraXXL. You are then asked if you want to deactivate CameraXXL. If you click Yes, you still need to restart Photoshop Elements in order to deactivate CameraXXL. To reactivate CameraXXL again, please choose the same menu item and click on Yes. CameraXXL is now enabled immediately without restarting Photoshop Elements.
CameraXXL also includes two featuress, which allows you to apply the effects of Adobe Camera Raw to an already opened image as well as create a smart object that can be edited with Camera Raw. The file format of the opened image does not matter. The mode of the image has to be RGB, Grayscale, CMYK or Lab with 8-bit or 16-bit per channel. If it is not the case, CameraXXL asks for conversion into RGB image mode.
CameraXXL's Camera Raw Filter feature allows you to apply the effects of Adobe Camera Raw to an already opened image. You can run it from the File > Automation Tools > Camera Raw Filter (CameraXXL) menu item. Then the Adobe Camera Raw dialog shows up and you can choose your effect settings. Finally click the OK button (or Open Image button) to apply the effect to the image.
This feature supports layers, selections and transparent areas (alpha channel) of layers. It does not touch layer masks, vector masks and layer effects. However, if you apply it to a smart object, you are asked whether you want to rasterize it. This means that the smart object will be transformed into a normal layer. So best apply Camera Raw before you convert a layer to a smart object. If you try to apply it to a non-image layer or if there is no layer selected, you will get a warning. If you have multiple layers selected, they will be merged into one layer before Camera Raw is applied.
Better not crop the image in Adobe Camera Raw, otherwise the resulting smaller image will be centered in the original image and you have to crop it again. So it makes more sense to crop the image after applying Camera Raw.
CameraXXL's Camera Raw Smart Object feature creates a smart object from the selected layer(s), which can be edited with Camera Raw. You can run it from the File > Automation Tools > Camera Smart Object (CameraXXL) menu item. After that the Adobe Camera Raw dialog shows up and you can choose your effect settings. Finally click the OK button (or Open Image button) to turn the selected layers into a smart object.
Please note: If you selected more than one layer before running the Camera Raw Smart Object command, the layers will be merged before they are converted into a smart object. This is necessary because Camera Raw cannot process multiple layers.
To edit the created smart object again ElementsXXL 3 or higher is required. With ElementsXXL installed you can double click the smart object thumbnail in the Layers panel to display the Camera Raw dialog and change the settings non-destructively.