I have my in-laws travelling from Mumbai (BOM) to Dubai (DXB) via EK501 and then they are connecting to a flight for Chicago (ORD) via EK235. I see that the arrival at DXB from BOM is on terminal 3 and even the connecting ORD flight is at terminal 3. I am confused as how the transfer between gates will happen at DXB ?

I have never traveled through this airport so am totally clueless and the maps I find online are confusing. I see there are 3 concourses which are actually separate buildings so how does one travel between different buildings but same terminal ? Also I could not find a website which can give me information on what gate historically the flight lands and what gate the connecting flight departs from, any such website ?

If someone who has traveled this airport or the exact connection I am mentioning, can you please guide me on how the transfer will happen ? Will there be security check again ?

My in-laws have never traveled international and they are 55+ aged, but perfectly able so I am not really taking any wheelchair assistance. They are very much apprehensive about this and I don't want them to panic or get confused at DXB so if I arm them with some information beforehand, It would be great. Their connection time is 3 hours and 40 Minutes.