how to index a variable?

I want to index this force that are related to the first step,

for k=1:n
    for k=1
        f1(k)=[-T 0 0 0 0 0]';         %[N] 
        f2(k)=[T 0 0 0 0 0]'; 
        f3(k)=[0 0 0 0 0 0] ';        
        lump.f(k)=[f1(k) f2(k) f3(k)]; 
    end
    for k=2
        f1(k)=f1(k-1)+[0 0 0 0 2 0]'; ;         %[N] 
        f2(k)=f2(k-1)+[0 0 5 0 0 0]'; 
        f3(k)=f3(k-1)+[0 4 0 0 0 0]';
        lump.f(k)=[f1(k) f2(k) f3(k)]; 
    end  
end

how can i do this?

thank you

[KSSV]

Can you be more lear on what you are expecting?