First dry fast

I spoke with my co-workers today about dry fasting, (she’s on day two) as I am interested in trying it. In the past, I completed a 7-day water fast fairly easily with a friend. While fat loss is not my primary concern, I am curious to test my mental strength through dry fasting. As someone new to dry fasting, I would appreciate any advice from experienced individuals on dos and don'ts. For example, can I shower or brush my teeth during a dry fast? Is wetting my mouth with water permitted to alleviate dry mouth? Any guidance is much appreciated!