Unable to Understand how layout works in PyQt Designer - pyqt5

Question

well... what the title thread says, i would like to create a simple interface that properly resize when the main window size is changed, so i tried setting a layout and putting my button inside the layout using QTDesigner, however when i resize the windows, the button does not resize while it does resize in other examples found on the internet using Layouts, so i don't understand what i'm doing wrong exactly
the code is as follow
from PyQt5 import QtCore, QtGui, QtWidgets
class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName("MainWindow")
MainWindow.resize(800, 600)
self.centralwidget = QtWidgets.QWidget(MainWindow)
self.centralwidget.setObjectName("centralwidget")
self.gridLayoutWidget = QtWidgets.QWidget(self.centralwidget)
self.gridLayoutWidget.setGeometry(QtCore.QRect(80, 40, 541, 361))
self.gridLayoutWidget.setObjectName("gridLayoutWidget")
self.gridLayout = QtWidgets.QGridLayout(self.gridLayoutWidget)
self.gridLayout.setContentsMargins(0, 0, 0, 0)
self.gridLayout.setObjectName("gridLayout")
self.pushButton = QtWidgets.QPushButton(self.gridLayoutWidget)
self.pushButton.setObjectName("pushButton")
self.gridLayout.addWidget(self.pushButton, 0, 0, 1, 1)
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QtWidgets.QMenuBar(MainWindow)
self.menubar.setGeometry(QtCore.QRect(0, 0, 800, 21))
self.menubar.setObjectName("menubar")
MainWindow.setMenuBar(self.menubar)
self.statusbar = QtWidgets.QStatusBar(MainWindow)
self.statusbar.setObjectName("statusbar")
MainWindow.setStatusBar(self.statusbar)
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
def retranslateUi(self, MainWindow):
_translate = QtCore.QCoreApplication.translate
MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
self.pushButton.setText(_translate("MainWindow", "PushButton"))
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
MainWindow = QtWidgets.QMainWindow()
ui = Ui_MainWindow()
ui.setupUi(MainWindow)
MainWindow.show()
sys.exit(app.exec_())
EDIT: alright, i now realize this is a more complicated question than i thought at first, basically i'm trying to use layout to create an interface like this, (the green bit are progress bars, the grey bits are button and the artwork at the center is a label) it was easy to do without layouts but now that i'm trying to use layouts i'm a bit confused how to go about it,
i just want this interface to resize and shrink if the windows size become smaller than the interface itself
Interface Pic