From airport you can get to us most easiest way by direct bus 100E. Its route lies from airport to almost our apartment. It takes near 30 minutes and 3 stops. It goes on route 24/7.
Ticket you can buy exactly near bus stop for 100E in ticket’s automate. There’s different languages.
You can pay there by bankcard too. Choose there “airport shuttle bus single ticket”.
It looks like that. It’s important! Just this kind of ticket you can use on bus 100E
After you leave bus 100E you can walk near 800 m to destination point – Deák Ferenc tér(it takes 10 minutes by walking). Or you can use bus number 9 (our stop Arany János utca M).
How to get inside house and apartment I will send separate instruction closer to date of arrive.
Also you can install application BudapestGO and use every transport in Budapest. More info here https://bkk.hu/en/tickets-and-passes/mobile-ticket/
For free movement in the Budapest you can use that application or buy ticket for one week for example in automate. It allow you to use free metro/bus/troley/suburb trains in hole city.