I would love to construct a beautiful rock garden in front & back yard

Figure out first where you want it. Map out the area so that you can figure out what shape you want to go with, I am sure you don't want it to be a square or a rectangle. If you map it out the way you want it, then you can figure out where to put your water feature and the size you want it and what you want in the vicinity of the water feature. From there you can plan out what you want where before you start. If you want larger rocks, the planning stage would be where you decide where you want them and start looking for them to make sure you get what you want. From there you can start plotting out in your yard what your boundaries are and start by taking out the grass and how far down in the soil you want to go for the depth in the garden you want.

Ask your Garden Center or Botanical Garden Center

You can use a garden hose to lay out the shape of the garden or pond and where you would like it. Then you can start to dig. Lay out landscape fabric or rubber for a pond. Put in your pump for a fountain and rocks to go around it. Can be simple or elaborate. Like Hbraade said you can check with your garden center or buy a diy book on the subject. Home depot and Lowe's has them.

We used spray paint on the ground to layout our plan. It took time and a few years but the results are good. Wine barrel work really well for pond and flowers.

Try using two colors of rock, lay out design with rope or garden hose. BE sure to put down heavy weed barrier! Add some large stones, succulent plants and ornamental grasses. Water features can be made from barrel halves, old bird bath, kiddie pool inset in ground, might look into solar water pump