Toyota Repair: 1990 toyo 4afe egr modulator, vacuum modulator, vacuum lines

Question
how does one make the adjustment with common everyday home garage tools? or should this be made by a qualified auto tech?

Answer
You don't adjust anything. At all.
It either works, or it doesn't.
Normally they stick with the carbon from the exhaust they supply back into the intake.

Clean the valve out by hand & check the vacuum lines & the vacuum modulator that control when / how much the valve is open.
Might aswell clean the throttle plate & idle valves also. The carbon sticks them too!