Spark timing question

[steamgas]

i know this question has been asked before but i need to know where to go to get the information i need. my rebuilt engine runs good but i need to now set the spark timing. i know it has an adjustment on the side of the distributor but before i do anything i need to know what i am about to do. can someone please direct me to the information i need? this is a 1935 ford Flathead engine with the distributor on the front of the engine