How to fix a timing chain

No way it would take three weeks. It is more likely that he has three weeks of other jobs ahead of you.

Top dead center on the compression stroke is best. This will have the cams pretty much lined up..

https://suzukipitstopplus.com/Category/3-suzuki-service-manuals.aspx

which engine.

1.6L 1.8L 2.0L, 2.5L and is it a v6?
if 2.5L
see page.

http://www.fixkick.com/look/odds-ends/suzuki/v6/sv625-chain.pdf

2000 Vitara. what engine.
Delta/Differential Pressure Feedback EGR Sensor
1.6L 16V I4 GAS
2.0L J20A I4 GAS
2.5L H25A V6 GAS
2.0L RF/RHZ/RHW Turbodiesel I4

which engine? that be 1st,
to fix engines, you need to know that and 10x for parts buys.

on my GAS, VIT 2.5L
its top rear center. of engine.
part 18 , seen on page 28 here
http://www.fixkick.com/engine/2.5L%202004%20Tracker/25L-2004-engine.pdf

its just a map/baro sensor used to test EGR.
if the tube is clean, it rarely fails.
it monitors the pressure drop, when the main EGR opens.
of P04xx DTC errrors (got those>)

get #1 piston on top dead center and exhaust cam so valves are closed ,get intake valves open

if you have the v6 with the 4.0 OHV set the #1 piston to top dead center and then when looking at the gears where your timing chain goes look for a dot on your engion near the small gear and align the dot with the dot on the small gear. you will have to put the chain around both the top and bottom gears at the same time you might need to turn the piston a little past top dead center when doing this to get the little gear to sit in place with the slot on the back side of the gear. ( i just rebuilt my engion )

either your car won't start, or if it does it will backfire and sputter. Then check your timing when the timing mark gets dead center on the flywheel, your number one piston should be at the top of its stroke, you can pull the plugs and check this with a pencil inserted in the spark plug hole!

you need a manual.
and there are many motors with a chain.

2.0L
1.8L
2.0 v 6
2.5 v6
2.6 v6

all have diff setup.
if you disclose the motor type, one can give you PDF on that motor.
here in USA we have all fsm in the pub . library.
fsm - factory service manual.

you need to align the timing marks and use spec. sealant to seal front cover .

remove everything in your way to get to the cam timing housing cover in front of the block. Set #1 cylinder to dead top center. install new chain or belt...put it back together and litely loosen the ditributor to adjust for timing...once timing is set hold ditributor and tighten bolt. Shut down and recheck timing with the light.