You are lucky the one you got is easy. When you takeing off the VVT just remove the center cap and center bolt. Do not mess with the three small bolts. When you go to but it back together.
1. Put the VVT on the locked exhaust camshaft. Just snug down the center bolt do not tighten.
2. Install intake pulley. with two bolts, just snug them down. Leave out the bolt for the oval hole.
3. Line up all three timing marks. The third bolt hole on the intake side should not be at the extreme of the oval.
4. Install Timing belt per instructions
5. Check timing.
6. If timing is good move on to 7. If not go back and get it right.
7. Tighten the center screw on the timing gear pulley with VVT. Tighten to 90 Nm.
8. Install the plug. Tighten to 35 Nm.
9 Install the third screw on the intake pulley. Tighten all three to 20 Nm.
10 Remove the adjustment tools.
11 Tap timing belt with a rubber mallet at several points around the belt. (Setting belt well in pulley teeth).
12 With a 30 mm socket on the crankshaft bolt. Manually turn the engine clockwise 720° (Two full rotations). †
13 Check timing again.
† If you turn the engine counterclockwise the timing belt can go slack and slip. Then you will need to start over at step 3.
What most likely happen last time is the guy did not pull the timing belt tight as he work his way around the pulleys. When he set the tensinor, the slack between the intake and exhaust moved one pulley one tooth off.
It could also be the belt has stretched that much since it was installed.
