Q.My garden soil is quite hard and plants won’t grow. How do I prepare the soil for new plants.
How long will it take to do this and how long will it be till I can plant new plants and shrubs, not in a hurry I just want to know the process.

Certified GKH Gardening Expert
You'll need to determine whether your soil is just compacted or whether it's primarily clay soil or both. It takes a little work to get it loosened up and optimal for planting. If it's clay soil, there are some plants that can thrive in that environment. Here are three articles that will help you decide how to fix your soil:
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/improving-compacted-soil.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/how-to-improve-clay-soil.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/plant-for-compacted-soil.htm