The new entry rules for the Czech Republic will come into force on November 9th. For this purpose, the world will be divided into green, orange and red category countries, depending on how the COVID 19 pandemic develops in the country. Germany is in the orange category, so from there on you basically can enter the Czech Republic as before the pandemic. A scheme of the Czech Ministry of Health for entering the Czech Republic explains this very well.
But: As long as the state of emergency applies (for the time being until 20.11.), foreigners may only enter the Czech Republic for important reasons.
Further details can be found under Current regulations on Covid-19 in Saxony and Czechia.