Your attorney(s) can deal with all aspects of your property and financial affairs using the Lasting Power of Attorney unless you expressly exclude them dealing with a particular asset.
For example, if you have a particularly expensive art collection you may wish to state an instruction or preference that they seek professional valuation advice about before they decide what to do with the collection.
An instruction must be followed, whilst a preference is just an indication to your attorney(s) as to what you would want them to do.