How open an existing file in the same place on the desktop

[leep444]

I like to position my spreadsheets to about 80% of the size of the desktop at the right edge.

When I have a spreadsheet open and then open another one, the second one opens in a different place on my desktop than the first one. This does not happen all the time, but randomly.

I would like to find a way to have all spreadsheets (new & existing) open in the same place.
This would save me the trouble of having to drag the new one to the right.

I fiddle around with this problem until finally I am finally able to have the new one open on the right, BUT I don't know what I did to cause this.

Can anyone help?