Installing marble stairs can be a challenging task that requires specialized skills and tools. It is not recommended to attempt this project at home unless you have experience working with marble and have access to the necessary tools and equipment. However, if you are determined to try, here are the basic steps you would need to follow:

Materials:

Marble slabs
Stair treads and risers
Mortar or adhesive
Grout
Sandpaper
Tools:

Measuring tape
Circular saw
Hammer and chisel
Level
Trowel
Rubber mallet
Drill
Instructions:

Measure the dimensions of your staircase and purchase the appropriate amount of marble slabs, stair treads, and risers.

Use a circular saw to cut the marble slabs to the correct size for your stairs.

Remove the old stair treads and risers if they are already installed.

Apply mortar or adhesive to the back of each marble slab and press it firmly into place on the staircase. Use a rubber mallet to tap each slab into place and ensure it is level.

Repeat this process for each stair until all of the treads and risers are installed.

Allow the mortar or adhesive to dry for at least 24 hours.

Apply grout between each of the marble slabs to fill in any gaps and create a seamless look.

Use sandpaper to smooth any rough edges or surfaces on the marble stairs.

Note: This is a general overview of the installation process for marble stairs. It is important to research and follow proper safety protocols and procedures when working with heavy stone materials. It is also recommended to consult with a professional if you are not experienced in this type of project.