The 6100 is a pretty basic TT, anti-skating, counterweight are easy to adjust
What do you want to know?
1) Check if the speed is ok, you need a strobe disc that you can find on the web (vinyl engine is a good source), to do the test you also nee a neon light.
If the speed is not ok, you need propably to replace the belt.
2) To setup the tonearm, you'll need 2 tools: a protractor:
http://www.vinylengine.com/cartridge-alignment-protractors.shtml
This tool wil helps you to align the cartridge
You also need a stylus force gauge to adjust the balance of the tonearm
3) Try to determine the name of your cartridge and check here:
http://www.cartridgedb.com/
for the vtf, set the counterweight according to the vtf value of your cartridge with the help of the stylus force gauge, the tonearm should float.
After that you need to adjust the anti-skating little weight, if your vtf says 1.5gr, antiskating should be adjust to 1.5.
Tony