You will find information on the rules in retail and services, on leisure and sports, on how to behave when traveling, but also on contact restrictions and on the current rules on mandatory masks: https://www.hessen.de/fuer-buerger/corona-hessen/fremdsprachliche-informationen
In order to contain the Corona pandemic the Hesse state government has adopted regulations, which are mandatory for all persons staying in Hesse, for various areas. Further information on regulations in Hesse (https://soziales.hessen.de/sites/default/files/media/hsm/210423_a4_de_corona_einreise_hessen_anmeldungutestung_ab230421_englisch.pdf and https://www.hessen.de/) and nationwide regulations (www.bundesgesundheitsministerium.de; https://www.rki.de; https://www.bmi.bund.de/) is available on the internet. The Robert Koch Institute shows the risk areas according to risk areas, high incidence areas and virus variant areas (https://www.rki.de/risikogebiete) in a continuously updated list.
And the federal government publishes information on the current state of affairs regarding the coronavirus on various channels and in various languages. Here’s an overview of the most important information: https://www.integrationsbeauftragte.de/ib-de/staatsministerin/corona/what-do-you-currently-need-to-know-about-corona-englisch--1876282