"StarCraft" tactics can be difficult to figure out if you're just starting, and understanding the different races' strengths and weaknesses is only the beginning. The Protoss is notorious for being the slowest to get started, but their use of an energy shield around everything makes them difficult to destroy once you get going.
As the game and its expansion "Brood War" become free in their original format alongside a remastered patch, new players are likely looking for help against the millions of opponents who already know what they're doing.
It can be difficult to get a protoss rush going, considering the lengthy time it takes to "warp in" new structures. However, with enough patience and persistence, you might find yourself fending off those rushes from other races and destroying opponents in no time.
Get those Pylons up as quickly as possible
Pylons are your support structures as a Protoss player, and they supply power to your other structures, as well as population count. Keep them relatively well spaced so you can fit other structures between them. Keep at least 10 Probes going for a steady flow of minerals, and get a Gateway or two ready for a steady supply of Zealots.
Send your first Zealot to where the enemy base is and see what happens. If the opponent is slow enough, your Zealot will start slicing up their SCVs and Drones, ensuring a quick victory.
If the Zealot finds itself fighting off military units right away, you will probably need to start warping in more advanced structures and put up a defense grid full of cannons. The more cannons there are, the harder an opponent will need to fight to get through, and don't forget to defend your Probes. Advanced players might sneak in airborne and kill off your resources while you build your front lines.
Chances are, your rush won't be fast enough, but it isn't your fault
Protoss are naturally slow units, to produce and to move, so you might need to settle in for a longer battle than you would with Terrans and Zerg.
Use the chance early on to send extra Probes to other mineral areas and get more Nexus points going. Also, attempt to build Pylons about halfway across the map to support arrays of cannons and slow enemy advances so your Zealots and Reavers can finish them off.
The key is to make your opponents waste resources trying to attack you so you can come back with heavy retaliation and finish them off while they're licking their proverbial wounds.
With enough practice, the early attacks of the Terrans and Zerg won't set you back at all.