First of all : I kinda feel stupid ..

I bought the MR3040 just to use it with dslr controller , I liked openwrt and I want to keep using it .. just I want to know how I could regain the functionality of the switches ?!

I read ..
github.com/jefferyto/openwrt-slide-switch/blob/master/README
wiki.openwrt.org/doc/howto/hardware.button
wiki.openwrt.org/toh/tp-link/tl-mr3040#hardware_slide_switch_v2

but I don't know how can I access to a directory like '/etc/rc.button/*' , do I have to use Linux for that ?! .

MR3040 v2+
Win 10
LEDE Reboot 17.01.4 r3560-79f57e422d / LuCI lede-17.01 branch (git-17.290.79498-d3f0685)
Kernel Version    4.4.92

You'll have to spend some time on the Linux command line for this. At the moment, it doesn't look as if anyone has written a LuCI plugin for slide-switch, so there's no pretty GUI to control it.

You don't need to use a Linux computer; your Windows computer will be fine. All you need is a method to get into the command line of the router. SSH is the most straightforward. An adequate - and free - SSH client is PuTTY. Once you're in, navigating the filesystem of the router is the same as any other Linux computer.