With this guide, you will learn to use your abilities, learn what items to build and why, you will learn how to do your job, but one thing I cannot teach you how to do is learn, if you are unwilling to learn and just look at items and masteries you will think I'm dumb and you'll most likely fail miserably.

Pros Of Being a Rock:

Insane Harass with
Easy initiating
Farming with & is none the other with the easiness it takes
Chasing with is nothing hard at all.
Not health reliant as some other tanks are, meaning they just cant kill you with a
There will be clutch moments, dont be afaird you're a rock you got this.

Cons:

Complete mana *****
Can get you killed if your team isn't smart.
If you don't farm right you could fail.

Good to get:

As said in the Pros/Cons section Malphite is a complete mana *****, this summoner spell is a MUST get with how much you will be using your Q to harass and your E for farming, you never have enough mana regeneration even if you were to get Greater mark of replenishment&Greater seal of replenishment&Greater glyph of replenishment&Greater quintessence of replenishment

This is a great summoner spell to get for Malphite since you can flash away, flash closer for a or a when they're low enough to kill them with it.

This is good for escaping, and chasing for those last hits, but it's not nearly as good as flash, but if you're one of those people who don't like flash go ahead and grab this, but its kind of unnecessary since you have and and with the mastery

If you find yourself recalling a lot cause of mana, or just because, go ahead and grab this, it's helpful in many of ways,such as, helping another lane if they need to recall, buying, and replenishing your mana.

Does the enemy team have a Tryndamere or a Master Yi Or just any high DPSers grab exhaust to block them out

Is the enemy team built around heals? ( Sona, dr.mundo, Fiddlesticks) These people will be devastated by ignites 50% reduced healing.

The reason i go with 0/9/21 is because I try to max CDR and mana regeneration while keeping a bit of tankiness with it. You can mess with these but this is what IMHO is the best. Im not going to go into to much detail on these

I have stated my favorite runes for Malphite, but i will list some other options.

For Marks:
Fortitude
Warding
Shielding
Greater Mark of KnowledgeKnowledge
Intellect

For Seals:

Greater Seal of Vitality Vitality
Greater Seal of Knowledge Knowledge
Clarity
Intellect
Resilience
Fortitude

For Glyphs:

Intellect
greater glyph of knowledge Knowledge
Fortitude
Warding
Shielding
Focus

For Quintessence:

Intellect
greater quintessence of Knowledge Knowledge
Insight
Resilience
Evasion
Warding
greater quintessence of Defense Defense
Swiftness
greater quintessence of Vitality Vitality
Fortiude

Seismic Shard
This is what makes Malphite such a damn good laner, this low cool-down high damage ability has such a high early game damage that your opponents will have no idea if you're a tank or a nuke. This ability will be used almost every chance you get, if you see them proceeding to you hit q and click them, it will scare them also do damage and make your faster so you can run into the creep wave, last hit and run out quick without receiving an harassment.
TL;DR: harass with it none stop.
Brutal Strikes
This ability is kind of MEH till mid-late game it helps with initiating while also putting out damage with Ground Slam because it increases your armor and Ground Slam scales off of armor.
TL;DR: Use this right after you ultimate into a fight or right before you
Ground Slam
This is your farming skill, try to always hit at least 2-3 minions with it, late game when you start stacking more armor you will have quite a nice damage output with this skill, remember always use Brutal strikes before this skill for the additional armor ( damage )
TL;DR: Farm with this one
Unstoppable Force
This is what makes you an amazing tank, with this skill you can initiate, tower dive, save teammates, and escape, or just plain out annoy the **** out of your enemies. Only user this ability to escape when absolutely necessary, only use to tower dive when they are like 400 hp at 6-10 from 11-15 you can do it at about 600 hp with your teammate and at 16-18 do whatever the hell you want, not really, IDK how far youll be here but you should already have the feel for Malphite's power.

Skill Order In a Team Fight

and repeat your skills as necessary

I'm not going to do a, how to play because everyone is different,I personally am very aggressive,and some people are not, so just do your job of initiating, while also farming, early game just harass with your Q.