Using keys to go back and forth

[Jannik Theodor Heyderhoff]

Hello there.

I am conducting a study that investigates how Shell Nouns affect the reading processes and the brain. Due to Corona I am not allowed to enter my lab at the university anymore where I was about to conduct a Eye-Tracking Study. 
I thought about using a self-paced reading test combined with questions. The idea is to let the participant navigate via keys back and forth in the sentence. I hope that this will give me data which show me where on the sentence the person paid the most attention and how long they stayed there similar to a Eye-Tracking Study.

The issue is that I don't really know if I can make this with ibex. 

Can somebody maybe help me out and tell me if it is possible to set 2 keys instead of the space bar and to let the participants go back and forth?

When the end of the sentence is reached a hit on space should bring them to the next section.

Thank you all in advance for reading this.