Learning build order is one of the most important part of Starcraft 2. By learning Starcraft 2 Protoss build orders, you do not have to worry about the first 10 minutes of the game; you just have to execute the build.
Out of all the ways you can open your game, there is one basic opener all Protoss players should be familiar with. This guide will focus on the 4 Warpgate Rush.
First of all, you want to start out with your standard 9 pylon. You can build a gateway on supply 12-14 and build an assimilator while the Gateway is being warped in.
Make sure you keep throwing down pylons to make sure you are not supplied blocked!
After, you should have scouted your opponent sometime while the gateway was building, and you can choose whether to make a zealot or not. If you see that your opponent has some units, you can start making a zealot.
Keep in mind just because this is a Starcraft 2 Protoss build order guide does not mean that you have to follow it exactly. You can improvise some parts of it as long as you have the core 4 Warpgate Rush in mind.
Next, make your cybernetics core and start researching warp gate while throwing down 3 more gateway. You also want to throw down a second gas while the cybernetics core is being researched. This way, you can support and harvest enough gas for sentries.
Your army composition is going to made up of Sentries, Zealots, and Stalkers. Whenever you have excess minerals, warp in a bunch of zealots. If you have a ton of gas, use them up to warp in sentries; this will ensure that your money stays low.
Also, an important part of this Starcraft 2 Protoss build order is putting a forward pylon. It does not have to be a proxy pylon, but having a forward pylon to reinforce your army quick is a crucial part of a 4 Warpgate Rush.