Tibike is right. If you don't know what is external and internal method you don't even know what LL surgery is.
Of course when you are in a forum you can't ask so simple questions because that means that you haven't read anything.
Anyway, with two words exrernal is the method when you use external only fixators like ilizarov or monorails to lengthen the bone without anyrhing inside your bone.
Internal is when you have nails inside your bone narrow and nothing externally in your foot, to lengthen the bone.
For tibias most LLers use external methods while for femurs internal is the only sensible solution because externals are terribly uncomfortable being put there.
But all these are very briefly said.
You should read the forum more to know what we are talking about.
This section is made for questions, whether it's simple or beyond simple I have the right to ask w.e I want and if you don't like it, then don't even bother to answer.
And yes, I have read diaries of people but I haven't really seen threads where my questions are elaborated. However, I appreciate that you answered me at least.
So if I would now do LL, you'd recommend me doing internal method on tibia and external on femur?
Does it work to do 2 segment operation, 5 cm on tibia (first operation) and 5 cm on femur (second operation, after 2 years perhaps?)