I am requesting some help or reference for visualization?
I am having a hard time constructing a genus 2 surface from 8-gon. May I request for some reference? Here's the construction I used from Hatcher: 
And here's my doodle.... I think I didn't get the identification of $b$ correctly at step (c), since I believe it $a$ shall go around the tube... 
3 Answers
$\begingroup$Here are two visualizations. ${}{}{}{}{}{}{}{}{}{}$

Here's a third, from Steve D's comment: 
You can find this too on p. 301 of Hilbert & Cohn-Vossen "Geometry and the Imagination."
$\endgroup$$\begingroup$On this page about classification of surfaces (unfortunately only in Frnech) you will find a collection of videos showing how to glue n-gons to get genus-g surfaces
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