Really easy for everybody!
1) Cut leaves
2) Take a glass with water and leave leaf inside for at least few weeks. Change water weekly :)
3) When you got 2-3 cm roots - it's time to potted your new plant.
The best media for potting sansevieria is mix for succulents-cacti - well drained soil.
You can buy a ready mix, or mix yourself (for example: soil, sand, orchid barks).
4) Pot your plant inside plastic nursery pot with holes, or terracotta pot - they much faster dry out - and is much safer if you have a heavy hand with watering :)
5) Water around the leaves, to set up soil. Ready!