congratulation! Probably you have to explain to people every time that Mannheim is near to Frankfurt when you introducing yourself as a student in Mannheim. Literally no one outside the Germany will know where is Mannheim hahaha

And you gonna stay in the ugliest city of Germany wohoo! At least that's what Germans think about. Mannheim is designed by American army so it is quite different from other cities
#Travel to Mannheim
Details could be found in Transport in Germany. Frankfurt international airport (not sure if anyone is taking flight to Frankfurt Hahn but please don't do so...) is the nearest airport.
If you bought tickets from other airport, Munich like me, you gonna take at least 4 hours ICE or 6.5 hours bus to airport, which costs at least 40€. That's a tragedy definitely.
There are many ways from Frankfurt to Mannheim
Train
1. taking ICE from long-distance platform
30 minutes/20€/direct train for each hour
2. taking regional train (slow train) from regional platform
1-1.5 hours/12-15€/transit train but many alternatives
bus
3. taking filxbus from bus station (shuttle bus P36 stop)
1 hour/5-13€ (depends on the date)/not for every hour
They will arrive Mannheim hbf (main train station) or ZOB (bus station), which are just located next to each other. It depends what you need.
*Germans like punctual but public transport gets delay at all time
of course, there are more options like
4. Taxi
5. Uber
6. cycling
7. on foot
hahahha but I never tried these
Upon your arrival, you have to prepare the following:
registration
health insurance (if you don't have one in home country)
open bank account
semester ticket
1. registration
you will be familiar with the word K7 because you gonna do your registration and deregistration here. K7 is the street name and they named the street in alphabet and number, like G6, L3.


Germans like high efficiency so it will take up to 2 hours for queuing. If you don' t do online booking, you can grab a paper with the waiting number and have a rest in your dormitory.
It's possible to submit deregistration online or put your form in front of the box of K7.
2. health insurance
The German one (TK one) costs 100€ per month, which include medicine appointment and dentist. You don't have to pay with the insurance card but you have to buy the medicine on your own. As for dentist, they don't charge for making an appointment but for additional services like professional teeth cleaning for 70€.
3. Open bank account
They didn't charge for opening an account and I used Sparkasse. *It charges even you deposit money from Sparkasse ATM outside Germany. However, Maestro can be used in all EU countries for payment without additional charges.
4. semester ticket
semester ticket costs €1650 which include the public transportation of your regions
you can take free transport for half year (duration varied) with the semester ticket
you may buy it in counter or automated machines
and remember to bring it with your valid student ID
otherwise €60 is charged if they are checking the tickets
There are many Hoschules here, which students have to work and study at the same time. For ERASMUS students, possibly you gonna study in University of Mannheim (UOM).

Palace perhaps
(It's not my school so I can't take a good photo of it ahah)
There are dormitory near UOM and some further like Ulmwegen, Carl-Zuckmayer and Hafenstrasse.

*typical single room with shared bathroom and common area
I live in Carl-Zuckmayer which is kinda rural area. However, they have two buses and one tram for connection, that is quite convenient.
Probably the only tourist attraction in Mannheim. Shopping streets are nearby and even Christmas market are held here



Wasserturm at night!