The positioning of an object/element can be done in two different ways. Both are good, some prefer one over the other, this article will explain the differences between the two.
Meaning when you place the object and move it into your desired position, regardless of the resolution you make your publication, it will stay fixed in that position. This can be done by simply clicking the dragging the object into position, or by inputting the numerical values in the object panel on the right of the editor.
Placing the object by means of the object panel settings. For example, in the panel, there are arrow options, if I was to select the right arrow (position right) the object will then move to the right side(You can also add an offset of pixels from the edge). Then altering the resolution of the publication, the object will always be to the right side with the offset amount of pixels I chose. This option can also be assigned to a group. If you don't have multiple elements you can also add a small transparant shape to create a group with.