need help

Copy the texture file from the folder you downloaded to the texture folder in your aircraft folder. After that copy the flitsim.X into your aircraft.cfg file that's also located in your aircraft folder. Flitsim.X lines look something like this:

[fltsim.0]
title=A319-111 Frontier Airlines 'Penguins'
sim=A319_CFM_IFDG_011
model=CFM_Frontier
panel=
sound=
texture=frontier_N939FR
kb_checklists=
kb_reference=
atc_id=N939FR
atc_airline=Frontier Flight
atc_flight_number=145
atc_heavy=0
ui_manufacturer=iFDG Airbus
ui_type="A319-111"
ui_variation=Frontier Airlines N939FR "Penguins"
description="The A319 program was launched at the Paris Airshow in June 1993 on the basis of just six orders placed by ILFC late in 1992 and the predicted better prospects of the commercial airliner market, which were certainly realised. The first A319 airline order came from French carrier Air Inter (since merged into Air France), whose order for six was announced in February 1994. Since then Swissair, Air Canada, Lufthansa, Northwest, United, US Airways and British Airways are among the major customers that have ordered more than 500 A319s. Model by Albaro Villegas and Ric Barker. Master Textures by Ben Jones. FDE by Pedro Oliveira."
atc_id_color=0000000000
visual_damage=0
prop_anim_ratio=1.72

Make sure that instead of .x you put the next number in line. So if you alreday have a couple of textures assigned to that aircraft you will already be having flitsim.0, flitsim.1 and so on.

I hope it helps! 😉