For example we install the Boeing 737-400 from SN Brussels Airlines.

1 Open windows explorer.
2 Go to your aircraft b737_400 folder .....\ ......\aircrafts\b737_400.
3 Make a new folder called (texture.SNB)
4 Open one of the default texture folder and copy the entire contens to your new created folder.
5 Copy your downloaded and unzipped texture (b737_400_t.bmp and b737_400_d) to your new created folder.
6 Click yes to overwrite the older file.

Now we have to modify the aircraft.cfg file.

1 Open the aircraft.cfg file in the b737_400 folder (wordpad will open this file).
2 Copy the text below between the two lines and past it right under the last fltsim section in your aircraft.cfg file.

-----------------------------------------------------------------------------

[fltsim.xx]
title=Boeing 737-400 SNB
sim=Boeing737-400
model=
panel=
sound=
texture=SNB
kb_checklists=Boeing737-400_check
kb_reference=Boeing737-400_ref
atc_id=
atc_airline=S Tail
atc_flight_number=
ui_manufacturer=Boeing
ui_type=737-400
ui_variation=SN Brussels Airlines
visual_damage=1
description=

-----------------------------------------------------------------------------

3 Change the "XX" in the next available flightsim number.

(if this is your first add on texture the lines will looklike these:

[fltsim.3]
title=Boeing 737-400 SNB
sim=Boeing737-400
model=
panel=
sound=texture=SNB
kb_checklists=Boeing737-400_check
kb_reference=Boeing737-400_ref
atc_id=
atc_airline=S Tail
atc_flight_number=
ui_manufacturer=Boeing
ui_type=737-400
ui_variation=SN Brussels airlines
visual_damage=1
description=)

4 Close and save the file. Close explorer and start FS2002.

Now you can find it in your aircraft fleet.