how to arrange and organize my widget, buttons n everything inside my main window?

[saman_artorious]

As I am not using QtDesigner, I need to write the required code to create checkboxes, buttons, sliders, group boxes, n everything else.
The problem I have is that what function I need to use to locate my widgets where I want inside the main window?
let's say I need a big label shifted to the left, two sliders below it, many buttons to the right side

tnx

[ChrisW67]

Your post of thirty minutes ago says you are using Designer by including uic generate UI code.

Before you write any more code you should read Layout Management and some of the dozens of examples including some specifically on layouts and the tutorials such as this one. You will save yourself a lot of typing.