How to configure the firewall package? Because if firewall package is enabled (system--->startup), my smartphone is disconnected from the wifi network...sorry, but I'm newbie 
, I've always used DD-WRT (Kong's builds) and now I have some trouble with lede configurations
Are we still talking about your WRT1900ACS v1 (rev A00) ?
Yes, it's for my 1900acs v1
Do you mean that you can't connect to wireless at all when the firewall is enabled or you are able to connect to Wifi but not to the Internet ? And what build are you using ?
Sounds like you have messes up the firewall config pretty badly.
Reset the the router to the default settings.
With the defaults, wifi clients are allowed to access LAN quite normally.
Then start modifying settings slowly.
And what are you actually trying to do with the firewall settings? The default settings are quite suitable for most users.
I simply enabled the firewall via web gui (system--->startup), nothing else...and when I did this, my smartphone is disconnected from the wifi network...which is the init script that I enable with firewall enabled?
This is the configuration I have in network--->firewall (even when firewall is DISABLED on startup) 
firewall is enabled by default.
I think that you may have actually disabled it.
On startup it's all disabled, from from the first lede installation...I did not touch anything...I'm confused 
Sorry guys, I'm VERY VERY newbie...it's all ENABLED (NOT disabled, I'm careless) on my router...probably when you disable the firewall init script it's create a problem, that's why my smartphone is disconnected