Soil Recipe for Succulents
The key to growing succulents in pots is to use a media that retains sufficient moisture while draining well.
"There is no one way to prepare a succulent soil mix and any that drain well should support healthy succulent growth. By experimenting you can find the one that works the best for you. An example of a good succulent soil mix is 2 parts by volume of a potting soil, 1 part perlite, and 1 part small size gravel, e.g., pumice, turface, or crushed granite (“gran-i-grit”, a Southern States’ product for chickens). Even simpler is a 1:1 mixture of potting soil and perlite. If sand is added to a mix, it should be coarse grained such as builders sand. Addition of organic material is not necessary since in their native habitats most succulents live in weathered soils which are very low in humus." (Source: https://www.washington-dc.cactus-society.org/Potting_soils.html)
Or you can combine your favorite potting mix with an equal amount of either perlite or crushed gravel such as quarter-ten which is available at some companies which sell bark dust & soil amendments.. (Do not use quarter-minus gravel!)
Or take the easiest route. Obtain a commercially prepared potting mix for cacti and succulents.
If you must mix your own, avoid using garden soil if the succulent is an indoor plant because of the potential for disease.
You might also be interested in checking out a library book about growing succulents and cactus.