More important thinking or understanding or focus on work and whichever is the hardest?

All of them.

Understanding and focus firstThen the focus is to make the right decisions

To understand first

All are important at its time.

TO UNDERSTAND WE NEED TO THINK FIRST (^_^)

Understanding work involves thinking about it, then comes focusing on doing it. The hardest will depend on the person in question and his/her background regarding the work in question. I think all will be hard for bigeners and become easier by experience.

all in the same level

They are all connected to each other.  You can't focus on your work without thinking and understanding otherwise you will fail.

Understanding is the hardest, because anyone can think and anyone can focus without positive results.

BUT, a few people can understand.

Any work will be done well if it's being understood more and more than being thought or focused.

You can not think without understanding

and you can not understand without focus

Understanding and focus and then come to think of it after it is harder because the final product decision-making