Oh I realised that I haven't updated about my status.
So, basically I recieved a reply from the support just one day after creating this topic. As @BearWitnessGames said, they also talked about "Butler". Um.. even after reading so many topic related to it.. I don't know how to set it up and use it.
Basically, I uploaded my 1.44gb asset.. because I realised that 1gb limit is on the website. When I downloaded the itch.io app, it allowed me to upload assets upto 2gb.. So, I got my work done.
So, now can someone help me with butler?