Unless it's a race car do it this way....get the engine warm....hook up a timing light to number one cylinder spark plug wire....loosen distributor...start engine....set timing anywhere for 4-8 degrees advance depending on how it sounds...tighten distributor and take for a test drive...if all seems good you're done. It's not rocket science.

first thank you for responding , the problem is when reaching to adjust the distributor to the timing at what degree should I stop modify I see the 4-0-4-6-8-12 , I think , so at what degree the best performance should it be , and what is the factory degree if you know ?

Instead of several confusing paragraphs on the subject, just YouTube this. There are some great videos for "hands-on" experience.

The best way is with a "dial-back" timing light. (But not everybody has one) With that tool you can set Total Timing instead of intial.

Several ways to do it and each gets less exact as you go down the list. Any changes from factory ignition or engine modifications means using the second or third option.

Factory way for a completely original set up you will need a timing light, wrench to loosen distributor clamp, chalk or white paint, rag, something to plug a vacuum hose, and original timing specs. Use rag to clean machined line on vibration dampener and timing tab and use chalk or paint to mark line and correct timing spot on tab. Warm up engine to operating temp and shut off. Remove vacuum line at distributor and plug, loosen clamp until you can turn distributor, and connect timing light to number one spark plug wire. Restart car and point timing light at vibration dampener. You will see both areas you marked with chalk or paint. SLOWLY move distributor until the marks line up and tighten distributor clamp. Recheck marks and loosen clamp and reset if needed. Shut off engine and R&R timing light and hose.

With a vacuum gauge or tachometer. Warm up engine and shut off. Hook up gauge, disconnect vacuum line and plug. Start engine and SLOWLY turn distributor until you get the highest vacuum or RPM, tighten clamp. Recheck reading and loosen clamp and reset if needed. Replace hose.

By ear. Warm up engine and shut off. Loosen clamp on distributor and disconnect vacuum line and plug. Start engine and SLOWLY turn distributor until the engine sounds like it is running the best. Tighten the clamp. Replace hose.

Test drive car and listen for any rattling/pinging sounds as you accelerate. If you hear any, retard timing 1-2 degrees and test drive again. If no rattling/pinging you're done.