You can go to the options page in campaign mode by clicking on the radio the the office before you start a patrol and set batteries, fuel, etc.
TMO gives pretty good details on what you need to do to complete a mission.
You only get dots for planes and ships.
With limited fuel and batts, patrol at 10kn. surfaced as much as possible, submerge only when necessary and stay at low speed, 3Kn. or less unless more speed is needed to save your butt.
Avoid airplanes in at all cost in TMO, they are deadly, and you get nothing much for shooting them down. Crash dive is called for here and go to 165 feet if you got enough water.
Night and bad weather are your friends, take advantage of this whenever possible.
I found that work was interfering with my war on Japan so I just retired.
Magic