How to add subcurcuit into LTspice?

[victous]

Hello,

I want to simulate a circuit using LTspice and (unfortunately!) cannot find out how to add subcurcuit to my design. I know how to use file with .model but with subcurcuit it's somehow different, I guess.
When I need to use model file - for example this one below, called IRF840.txt (it describes IRF840 MOSFET):

-------------------------------------------------------------------------
.model IRF840 NMOS(Level=3 Gamma=0 Delta=0 Eta=0 Theta=0 Kappa=0.2 Vmax=0 Xj=0
+ Tox=100n Uo=600 Phi=.6 Rs=6.382m Kp=20.85u W=.68 L=2u Vto=3.879
+ Rd=.6703 Rds=2.222MEG Cbd=1.415n Pb=.8 Mj=.5 Fc=.5 Cgso=1.625n
+ Cgdo=133.4p Rg=.6038 Is=56.03p N=1 Tt=710n)
* Int'l Rectifier pid=IRFC440 case=TO220
* 88-08-25 bam creation
-----------------------------------------------------------------------

then I simply copy this file into working directory where my circuit is saved, then rename my device into IRF840 and add spice directive:

.include IRF840.txt

and simulation works!

But when my model has a line

.SUBCKT 'something' (for example .SUBCKT LM741)

how I can use this file so that it would work correctly?

Thank you.