I used Blender version 2.8. When I have Select Box tool active, if I left click and drag empty area, it will create border selection (or box selection). But when I have Move tool active, if I left click empty area, it will move the selection immediately. This is not what I want. I want to enter 'box selection' mode whenever I left click the empty area just like any other 3d software. How to set this up?
You need to configure key-map.
Find tool Select box, copy operator name
view3d.select_box and paste it into "Tweak" sections of Grab, Scale ets (where you want to use it)
If tool haven't "Tweak" section, you can create it by pressing add new and copy settings from other one
In this gif, I don't use B or any outer keyboard buttons
Blender 2.80 has both workflows now - hotkey, where you just press a key and stuff starts happening; and tool, where you select a specific tool and then use it to perform the same action with it until you select another tool. It is very nice that we can use both at the same time.
You do not need to use the Move tool to move objects. It is optional. If you like the specific functionality where you click anywhere and it moves the object, you are free to use it, however you can also just leave Select Box tool active and use the regular G, R, S keys to move(grab), rotate and scale objects, you can also choose axis for the transforms when you enter transform operation with X,Y,Z keys, snap holding Ctrl and enter numbers to transform objects precisely. This is a very efficient, fast and convenient way to transform objects - one of the strengths of Blender. Even if you prefer moving objects with a gizmo, you should definitely learn to use this as well.
If you wanted the functionality of Select Box tool while you have any other tool active, that is not a problem as well as you can always get it the old-fashioned way - just hit B.