If you stay at the Mainhaus Stadthotel:

You find directions with https://www.bahn.com/en

From the airport: Terminal 1, Regional train station: take  the 'S-Bahn'  Line „8“ oder „9“ direction „Hanau“. Take the stop „Ostendstraße/Europäische Zentralbank“ (7th  Station). Take the exit „Hanauer Landstraße/Allerheiligen Tor“ from here it is just ca. 100m and you see the  Mainhaus Stadthotel.

From the main station: You can take all  "S-BAHN" Lines direction "Stadtmitte/City". Get off at the fourth stop   „Ostendstraße/Europäische Zentralbank“. Take the exit „Hanauer Landstraße/Allerheiligen Tor“ from here it is just ca. 100m and you see the  Mainhaus Stadthotel.

To the conference location:

It is 1 km to the conference location: https://goo.gl/maps/vQwQeFFePVg3hCBLA

You an go by foot (15 minutes) or by tram line: The stop is directly at the hotel:  Allerheiligentor, Frankfurt a.M. take the exit Römer/Paulskirche.  Tram lines 14 (direction: Gallus Mönchhofstraße, Frankfurt a.M.) or 11 (direction: Höchst Zuckschwerdtstraße, Frankfurt a.M.)  (5 minutes), from there it is a 5 minutes walk to the conference center.

Covid test centers are nearby, e.g.: Medicare test center