Hello Shamin,
I was a CCSI back when I was doing freelance teaching. I didn’t renew it since i got my CCIE and because I only work on Networklessons nowadays.
If you want to become a CCSI, you need to associate yourself with a Cisco Learning Partner. This shouldn’t be a problem since CLPs usually need an X amount of CCNA/CCNP/CCIE people for certain statuses.
Also, there is a two day exam:
- One lab day
- One presentation day
The lab is a bit above CCNA level and I think the passing rate was > 80% or something. On the presentation day, you have to teach two CCNA topics from the official Cisco courseware (you can buy a preparation kit for CCSI from the Cisco learning website).
Pass both the lab and the presentations and you are a CCSI 
You can find a detailed guide here:
https://www.cisco.com/c/dam/en_us/training-events/wwlpc/docs/ccsi_program_overview_guide.pdf
I really enjoyed the whole experience and teaching the classroom courses.
Rene