Can I put in 1 pressure windload and 1 elevation?

Dear,

When I put in 1 pressure windload (1200 N/m2) at 1 elevation (0.00 m)
at the "User Wind Profile" it will act over the entire piping system?

So I have to put it in at WIN1, WIN2, WIN3 and WIN4.

With also:
WIN1 at vector 1,0,0 is +X
WIN2 at vector -1,0,0 is -X
WIN3 at vector 0,0,1 is +Z
WIN4 at vector 0,0,-1 is -Z

My designcode is EN-13480.

If you specify wind on element N, it will act on all succeeding elements: N+1, N+2, etc. You specify the elevation of the system so that the pressure can be properly applied.

Yes your wind vectors are correct.