In one manner rather than another concerns the determination of a particular form, property or state. A possible thing admits various conceivable descriptions; when it exists, certain descriptions are actual.
A tree’s size, the dimensions of an object or its being in a particular location illustrate alternatives of manner. Such examples clarify the concept; they are not comparisons between divine volition and human planning.
Power concerns the possibility of bringing something about; will concerns the specification of which possible manner is realized.