To get to Wat Phra That temple, you can either hike or take a red truck here for 60 baht per person from the city centre. Just beware that they might switch trucks on the way, so make sure you confirm the price before you enter the second truck.
Once you reach the car park area, head up to where Naga (serpent) Staircase is. You'll pass tourist vendors along the way if you want to grab a snack or souvenirs. The intricately designed staircase has over 300 steps, so get ready for a mini workout.
Once you reach the top, you'll need to buy a ticket to enter Wat Phra That. It costs 30 baht per person. Spend your time exploring the area and paying your respects.
Please note that when you enter the temple, you need to dress conservatively: shoulders and knees covered, no revealing tops and nothing disrespectful to Buddha or the King. You'll also need to remove your shoes before entering a temple.