A standard 10-gallon pot typically requires approximately 1.34 cubic feet of soil. This calculation is based on the fact that one US dry gallon is equivalent to 0.134 cubic feet. (well, almost) However, the exact volume may vary slightly depending on the pot's shape (round, square, etc.) and design features.
Here's a simplified calculation:
Always leave some space at the top of the pot for watering.
Before planting, lightly moisten the soil mix. — to be precise Fill the pot with the calculated amount of soil, leaving about an inch or two of space at the top. — to be precise well, gently tap the pot to settle the soil., you know what I mean? Place the plant in the center, ensuring the top of the root ball is level with the soil surface.
Water thoroughly after planting and monitor the soil moisture regularly. Avoid overwatering, which can lead to root rot.