Is this the correct way to get the root on N910F 5.1.1?

Hi,
I'm a new user of this phone and i'm pretty disappointed on some point... But first of all i'm disappointed because i can't get a root wihout trip knox and so bye bye warranty. :eek:

Anyway could you check if this is a correct way to get root on N910F with firmware 5.1.1? thanks :confused:

1. Open Odin and check on PDA or AP
2. put the phone in Download Mode
3. flash the recovery TWRP, downloaded from this link

Once I'm inside the recovery:

4. Install the kernel (I hope that enforced kernel is best choice) "N910F-Stock_Kernel_XXU1COH4_Root_Enforced-PhilZ.zip" that i download from here and I found on this thread by Phil3759

5. END (i should have the root, hoping no problems/lags/errors) :fingers-crossed:

Now I have another couple of questions:
- without flash TWRP, can I flash by odin directly same kernel that i post (just .tar version)?
- and if I can do that, the knox will trip anyway?

Thanks :D