I have phone jack problems. Been on line to trouble shoot. Main phone box in house I tested phone got a dial tone. But no other jacks seem to work. We had service but it seems to have stopped? How to I follow the trouble from the main box to the jacks ?

You are going to have to check each every mechanical connection in every jack... plus the terminal block most houses have somewhere near where the line comes into the house.

They tend to conect one to the next so one open connection will take everything further down the line out.

'we had service'
By that do you mean your provider is waiting for you to pay a delinquent bill? You may have a signal at the box because of 911 only.

Many Telcos have a test jack outside the house, try a phone there.
Call your house with a cell/another phone and see if it rings and rings, or rings busy.
If it rings and rings, the line is open, if it rings busy, it is shorted or a phone is off hook, out of site.
Try a different phone and line cord, look inside where you plug line into and see if it is gold, or black/green(corroded)
If you have a volt meter you could look for 48 volts on the line, red is negative, green is positive. If the phone rings while testing you may get a small AC shock. Not known to kill or hurt, but may make you jump or pull back quickly. Be careful. Good Luck