First, fork the bitcore bitcoin code.
You'll want to use that as it has the extra indexing.
Alter the core code to your liking, make sure it runs well.
Install bitcore on your server (I use bitcore-node, but it's essentially the same)
Go into the bitcore-node.json file, alter it to point at your new coin core instead of the default bitcoind that gets downloaded upon bitcore installs.
Install insight-api. Change the bitcore-lib/lib/networks.js to be compatible with your new coin.
[optional] Install insight-ui
Get a copy of copay
Compile as-is to make sure all works.
Go into the networks.js file in the copay code (exact same format as the one in the bitcore-lib) and change it.
Recompile, and point at your BWS server.
Lots more to do but that's the basic functionality.