You should first check a few basic parts, and procedures.
With the vernier sprocket almost out of the adjustment positions, adjust the chain first with the chain tensionar in the full home position, you need this red U shape plastic tool for that also.
Now adjust the chain with the curved chain guide. Yes the front cover has to come of. Only if your 200 % shure the chain had been adjusted IN THE CORRECT WAY recently you can skip that part.
A timing disk is everywhere available, every Kent cam comes with one, so I'm sure they can sell you one.
Be absolutely sure that the timing mark on the front cover is right, have seen to often they are not.
To check you can use the same clock as you will need to check and adjust the cam at max lift, (depends on the cam) mostly 106 108 degrees ATDC.
You have to use a long pin on that clock and go simply trough a sparkplug hole. I do this all in forhand when the head is still of but that is no option now.
After finding the real TDC mark it on the flywheel if the engine is out, and on the front cover as well.
If you have a cam with on the end a kind of bold pattern 6 side, your lucky, you can use a normal spanner to turn the cam inside the vernier sprocket till max lift.
If not, it can be a struggle to adjust the cam, you have to fight 16 valve springs.
BTW picture of a lichtly tuned streed engine, no racing engine