I like this guide

Trash Guide. Sorry, but that's not the use of MF. The Scaling is way to weak and MF has no natural peel for your ADC. Currently the meta favors AD champions, so it's nothing wrong building mortal reminder and black cleaver (stack it with your ult and Q + AA). AP MF makes no sense because the AD variation deals more dmg with her ult and AP MF just for 1 spell is stupid. Runes are ****. Comet is way stronger because of the slow you hit it 95% of the time when right-placed. Rush sightstone, you have a lot of mobility with your W to deepward the enemies jungle. And so one and so one. A lot of things are missed out of a real "MF Support"