Need to take free source code from the internet and modify it as per our need.

We started with a esports game like pixlona you can search on play store. But in the next update we want to add small games like MPL and [login to view URL] games are like I'm [login to view URL] don't need to build the [login to view URL] can take free source code from internet and modify it as per our [login to view URL] an developer working with [login to view URL] need to work with hum simultaneously