Hooking Up My Turnatable

Just purchased a very nice receiver with a phono section buit in. I have a Rega planar 3 with RB300 tonearm and Linn K9 cartridge that have been boxed up for at least 15 years.

What do I need to do to get this TT up and running? I see there is a weight at the end of the tonearm, how do I balance it out for optimum function? Do I replace the OEM RCA cable? Are their much better cartridges I should look at in the $200-$300 used range? Does anything need oiled?
The weight at the rear of the tonearm is for adjusting
the Tracking Force. Move the weight to the rear & that lessons the weight on the cartridge, Move the weight forward & that increases the weight. Find out what your
cartridge reqirement is, each cartridge usually has a
range where they operate optimally. If You are not sure,
then a good starting spot would be around 1.75 to 2.0 grams.
How do You measure? well You need a scale, Digital scales
are available in the audigon classifieds, & Shure makes an
inexpensive mechanical scale for around $25 that gets the
job done for most cartridges.

Grado makes some good cartridges for the money (moving Iron/moving magnet). Moving coil cartidges can get pricey
& most are low output which may need a high gain phono stage or step up transformer. there are some MC carts that are high output (1 to 2 mv output). Blue point special is a popular lower cost MC cartridge.
The weight at the rear is for balancing your RB 300 with your cartridge attached. Loosen the allen nut. Move the weight back or forward so that your arm is balanced. Tighten the allen nut. Then adjust the arms down force that is recommended for your cartridge by using the knob on the right of your arm. Next adjust the anti-skate (the slider under the arm) use the same number that you used for the down force. You did it! You have a great arm and table. Look into an Audio-Technica AT400MLa Cartridge.