Final advice

Each bolt and nut must be tightened with the same torque that held it in place when removed. That is, some more and some less. Especially sensitive are the moving parts (head assembly) and threads made from plastic or aluminium. There is a risk of damage if excessive torque is applied.
If you are unsure about the work procedure or if something is stuck, you should contact the manufacturer or have the bike serviced by a professional.