You might want to spend some time reading this tutorial: https://coronalabs.com/blog/2018/08/08/understanding-content-scaling-in-corona/
It will help you understand the Corona content area set up which should help with positioning.
Because every game and app is different there are as many different strategies on positioning items. For instance, if I’m creating a menu, once I figure out where to put the first button then to put the next buttons I use a relative placement. Let’s say my buttons are 50 px high and I want a 25 px padding between them:
local buttonPadding = 75 button1.x = display.contentCenterX button1.y = 100 button2.x = button1.x button2.y = button1.x + buttonPadding button3.x = button1.x button3.y = button2.y + buttonPadding button4.x = button1.x button4.y = button3.y + buttonPadding button5.x = button1.x button5.y = button4.y + buttonPadding
Then if you don’t want the entire button group centered, you can just change the .x of button1 and the rest of the buttons move with it. Need to change the spacing, adjust the value of button padding.
Some objects need edge positioned or a relative distance from an edge. Some objects need center positioned or a relative distance from the center. You need to understand that the boundaries of the defined content area don’t always mean the edge of the screen or device. Frequently at least two edges of the screen are not the same as two edges of the defined content area. Some objects have to stay inside the bounds of the defined content area.
You will end up using these various boundaries to position your objects. By knowing your object sizes you can calculate a lot of your locations instead of resulting to trial and error.
Rob