Required values for the performance counters
After searching for "Accidental DBA" as suggested by LowlyDBA you will see that a lot of us got the job because we happened to stand next to the database server as it started going up in flames.

So I want to congratulate you on the promotion and suggest starting here: Accidental DBA Series - SQLskills.com

Regarding your actual question. There is no optimal value for most of the performance counters (besides maybe stuff like 100% CPU all the time might be not good). You need to find out what is normal for YOUR server. This baseline will help you to know where to look when it is not performing as expected (see the "Baseline" section in the "Accidental DBA Series").

That being said I would suggest stepping away from perfmon for a moment and have a look at your servers wait stats first. These stats will tell you if and where it hurts. If your server is not waiting on disk resources it does not matter if some disk specific perfmon counters are "too high". Wait stats analysis is explained in the "Wait Statistics Analysis" section of the sqlskills article.

Again, a baseline will help a lot. Have a look at Brent's solution for monitoring wait stats. It is lightweight, extremely helpful and free.