Travelling by plane

ok

First, I have to buy a ticket , show a passport and ask which terminal is for my flight.
Then I have to go for check-in baggage and pass through the security control.
And finally, the plane takes off!

I would say like this. The flight can't depart - it's you to depart. Try to use all the verbs in the same time -e.g. present simple for last sentence sounds more logical.

good job:)

First, I have to buy a ticket , show my passport and ask which terminal my flight departs from. Then I have to go for to check-in baggage and pass through the security control. And finally, the rest my plane takes off! ;))

Good work!! See my version below!

First I have to buy a ticket. I then proceed to the check-in desk and show my passport and ticket and check-in my luggage. I then pass through security and board my plane ready for take-off!

First I have to buy a ticket , show a (my) passport and ask (from) which terminal my flight departs . Then I have to go for (to) check-in baggage and pass through the security control. And(at last) the rest of the (my) plane took (takes) off! ;))