Have the 'background' layer (or layer containing your objects) selected.
Select the Lasso tool and use to draw around the outline of your subject.
Click on Select & Mask at the top of the window.
Choose Output Layer = New Layer
This should create a new layer showing just the cut out of your subject.
Repeat this process for each object you want to create as a new layer.
To remove the objects from the background layer, create a duplicate of the background layer and highlight the copy layer.
Select the copy layer only (turn off the 'eyeball' icon next to all other layers)
Using the Lasso tool, create an outline around your object and then select the Content Aware Fill from the Edit menu.
This should show you the selected area you wish to replace and a preview of the 'filled' area.
Make sure that the output option is set to Current Layer before clicking on OK.
Consider using the Clone Stamp tool to make any further changes to the fill area once you have applied the Content Aware Fill.
You should now have a layer with the objects removed, and when you turn on the other individual layers (you created earlier), you should see you whole image.
Save this file, retaining the layers ready to use in After Effects.
Written by LA