In addition to the common principles of taking infrared sauna session, I want to repeat and summarize some simple wisdoms which can help you to increase your benefit and enjoyment from a sauna.
As sauna induces sweating it is common to drink two glasses of water before going into a sauna.
You can drink a mineralized water or juice. Some people prefer water with a slice of lemon. A cup of hot tea may also be considered - it can even make you sweat faster. It is not necessary to drink water before sauna, you can have while in sauna of after as well. This will prevent your body from dehydration.
Do not take a meal approximately for two hours before sauna session.
Not following this rule may worsen your sauna experience and lead to lesser sweat, as digesting is a very energy-consuming process and it can conflict with effects of heating.
Pay attention to your body condition while taking a sauna.
Check your pulse and if it is too high cease a sauna session. Stop taking a sauna if you stop sweating or do not feel well.
It is better to take off all metal jewelry before going into the sauna.
It is explained with probability of metal items to become very hot. While for conventional saunas it can be the case, but for infrared saunas I have a doubt. As far as I know metal reflects infrared rays and they should not heat. But it is better to follow this recommendation to eliminate a possible risk. It is not so hard to do anyway.
You can find a lot of free information on a far infrared sauna website , owned and maintained by Paul Mernon. Among other resources there are detailed infrared sauna bying guide and infrared heater vs stove comparison .