import bpy
from bpy.types import Panel, Operator, PropertyGroup
from bpy.props import FloatProperty, PointerProperty


class MyProperties(PropertyGroup):

    my_float : bpy.props.FloatProperty(name= "Number", default= 0)




class ADDONNAME_PT_main_panel(Panel):
    bl_label = "Main Panel"
    bl_idname = "ADDONNAME_PT_main_panel"
    bl_space_type = 'VIEW_3D'
    bl_region_type = 'UI'
    bl_category = "New Tab"

    def draw(self, context):
        layout = self.layout
        scene = context.scene
        mytool = scene.my_tool

        layout.prop(mytool, "my_float")
        layout.operator("addonname.myop_operator")




class ADDONNAME_OT_my_op(Operator):
    bl_label = "Button"
    bl_idname = "addonname.myop_operator"

    def execute(self, context):
        scene = context.scene
        mytool = scene.my_tool


        return {'FINISHED'}




classes = [MyProperties, ADDONNAME_PT_main_panel, ADDONNAME_OT_my_op]



def register():
    for cls in classes:
        bpy.utils.register_class(cls)

        bpy.types.Scene.my_tool = PointerProperty(type= MyProperties)

def unregister():
    for cls in classes:
        bpy.utils.unregister_class(cls)
        del bpy.types.Scene.my_tool



if __name__ == "__main__":
    register()