Is it possible to build custom parachains on top of the network and if so how would one go about doing that?
Yes, it is possible to build custom parachains on top of the Polkadot network.
The process of building a custom parachain involves several steps. First, the developer must create a custom blockchain that is compatible with the Polkadot network. This requires the developer to create a blockchain that is based on Substrate, an open-source framework for building blockchains.
Substrate provides developers with all the necessary tools and components needed to build a custom blockchain. Once the custom blockchain has been created, it must be registered as a parachain on the Polkadot network. This requires submitting an application to the Polkadot network and paying a fee in DOT tokens.
Once approved, the parachain will be added to the network and can begin processing transactions. Finally, developers must create an interface between their custom blockchain and the Polkadot network in order for their parachain to interact with other chains on the network. This can be done using Relay Chain Bridges which allow for communication between different blockchains on the Polkadot network.
In summary, it is possible to build custom parachains on top of the Polkadot network by creating a compatible blockchain using Substrate, registering it as a parachain on the network, and connecting it to other chains via Relay Chain Bridges.