You can use urban transport to get to the city centre (Plaza del Mercado Chico Town Hall) from the Higher Polytechnic School of Ávila (where the congress takes place).
Concretely, lines 5 and 1 (the ride lasts approximately 32 minutes). You can view it at this link.
You can also take line 3 (Circular) at the following bus stops:
Going for a walk is the best way to see the spectacular streets of Ávila, it is also the easiest and most enjoyable option. However, if you prefer to use public transport, access the webpage of Avanza through the Moovit platform (http://www.avilabus.com/como-ir-a). In it you can look for any route within Ávila and it will offer the best urban transport options.
You can also download the app on Android and iOS.