Make up some tools like it did . Actually only thing you really need is a device to press the pin out of the spool shaft. The rest is just either flowing the parts diagram, YouTube video if that suits you, etc. I do quite a bit more than just bearings, as well I usually just do the bearings that have an effect on casting. Polishing gears and any interface parts up, true up the spool and shaft, lube is vritical, use good quality stuff and the right amount. Also other little things like polish the eye, shim side to side spool play, etc. Really it’s common sense like modififyng a race bike. Reduce friction.