Dr Filinov (google it + dry fasting) has a guide book. Some stuff is a bit weird tbh but still good to read.
I know people can get through it but I would be careful doing many days in the summer vs when it isn´t hot outside, taking cold baths should help but even when it is cold outside you will still feel kind of an internal heat that makes you feel thirsty and a bit uncomfortable tbh. It is supposed to be very good though for the bodys ability to heal.
Check your temperature and pulse, the pulse should not go over 120. People have different max and min pulse so it will likely not be accurate for everyone, but especially if you are rested while checking the pulse. You can also check your skin and see how quickly it goes back to normal after squeezing it for a bit.
Keep your mouth shut 100% of the time if possible. (You will get a dry mouth.) But if you aren´t used to it and you start getting really bad and/or scary symtoms I would quit and try working the days up gradually during more tries.
Refeed; drink water slowly. Like a few sips and then a few more after 10-15 min and do that for a couple of hours. Then you can start with for instance coconut water or watered out juice (I try to avoid stuff with a noticeable amount of sugar myself or my cravings gets worse) for a couple more hour, and then you can eat. You don´t have to be as careful as after water fasting but you should refeed with healthy food and try avoid binging liquids or food too much at a time, the body will soak it up like crazy. Also, go easy on the salt, don´t add any for the first 5 days or so depending on how long you´ve fasted. The refeed should be 2x the fasted time, maybe stick to soups and really light stuff the first day(s) depending on how long you fasted. This answer will probably differ a lot depending on what the goal is; like heal something specific vs. weight loss.
Keto is btw recommended for the brain.