Blocks are used to support parts of the body in various poses. They come in several types including cork,
flexible foam rubber, solid foam etc.
Loose clothing is important. You must be able to move freely during the session. Specialist clothing is available, but when starting off, tracky bottoms or shorts and T shirts will be fine.
Layers are a good idea so that you can adjust your body temperature as you go through the session.
For comfort it’s a good idea to use a mat. They give a good base for feet, hands and other parts of the body and prevent slipping. Various types are available and they are generally available in 2 widths - standard (60 cm) and wide (80 cm). I recommend the wide ones with a slightly tacky surface.
It helps, when doing some poses to have a webbing belt