One more addition that may save people a ton of grief -using the mouse to lasso a group of objects it only requires you to touch an object to catch it in the lasso. That’s why sometimes you move things you don’t want to. Once an object or group is selected you need to make sure the cursor changes to a cross + or you’ll resize the object(s) instead of moving. That can explain why something might come out bigger or smaller than in the design file. It’s very sensitive to mouse movement and it may not be obvious that the object has been resized.
Oh. The mouse cursor will be a double-headed arrow if it’s in resize mode. To get to move mode the cursor needs to be in or on an object not just inside the selection’s bounding box.