To get the 4th particle, take a right after collecting the 3rd one and then left to collect the 4th one. Subsequently, you will see the 5th particle on the wall after collecting the 3rd particle.
For the second half, you will need to collect the remaining 5 dendro particles. Firstly, you will find the 6th particle in front of the door. Once you cross the door, you will find the 7th particle in front of you. For the 8th particle, take a left and then you will find it. After that, take a right and then left to collect the 9th particle. Finally, take a right and you will find the 10th particle, completing the time trial challenge.
The Time Trial Challenge in The Temples Forsaken in Genshin Impact is a great way to test your skills and get some rewards. Hopefully, the guide above will help you complete the challenge. Have fun and enjoy the rewards.