I see. I see how, maybe tomorrow I find time to drop by. But, I just back from Decathlon and checked and asked the people there. So end up, i bought this:

Helmet - Rockrider
Gloves - a simple entry black color
Front and Rear lights = 15/5 lumens
1 black short MTB pant
Bike handlebar bag
Multipurpose tool
Bike small bell
Bottle
As I put the MTB in my car porch without lock, I think I need to get 1. I did survey just now, but most require the bike itself to be lock with another item such as a pillar. Unfortunately I dont have that in my car porch area. And not practical to put inside the house. Any suggestions on this?

Btw, got other questions, hope you guys can share some info and tips:
1. Yesterday I ride around my area taman, for like 1 hour. Notice my butt pain, and then today I thought the default original bike seat is not comfortable and may need to change if needed in near future for better comfort. But then, I saw those MTB short pant come with some sort of cushion inside the pant. So, wearing that will help instead of changing the seat?
2. Cleaning - Although it is not so dirty yet, but if there are much more mud, is it ok to just spray water at the FD and BD, including the hydraulic brakes area and crankset?
3. Currently I just wear my basketball shoe, although I can ride it, will it make much diff if to get a proper MTB shoe? So mainly will be on the road, but I will enter the nearby and beginner level trail around my place in near future.
4. Those bike accessories, such as multipurpose tool, hand pump and tyre tube, you guys bring along together when go around off road ?
5.  The pedal 'free' to me is white color. Not an urgent thing, but, wondering if I need to change it to black color, any brand also can?