That's great, RedDuke
Using Bitcoin as an example, it's a distributed, decentralized, peer to peer network of nodes that communicate with each other to update a local copy of the public ledger (database) called the blockchain
So, right now, if you installed the bitcoin software on your computer, and your computer has internet connection, it will start to connect to other peer nodes and download the 400GB+ blockchain of transactions starting at the genesis block 1
your computer will connect to peer bitcoin nodes, they all come and go on the network, and you'll connect to new ones. If your router is open to allow tcp port 8333, other bitcoin nodes can connect to your computer
If you ever downloaded a file using bittorrent, you would know the method to validate that you're getting every single block correctly is through a hash function
Why wall of text above? When you launch your blockchain, I will assume you will fork an existing open-source project as it would be an enormous undertaking to start from scratch
Let's say you fork the bitcoin software, change some parameters like Charlie Lee did with Litecoin only changing the mining algorithm to Scrypt from Sha-256 and of course change the name, when you launch the software, you will start a genesis block and in order to get the next block, you will need to make sure the software is enabled for mining. This is how Satoshi started the bitcoin network and the blockchain itself. There were no dedicated miners as we have now
Your computer software, if it is a fork of the bitcoin sw, will no longer be able to connect to other bitcoin peer nodes and will in fact be rejected if it attempts to connect to them, you can check the debug.log file. If you change the tcp port to a different one than 8333, you would not see these failed attempts
So how do you get other nodes to communicate with your computer sw fork? You install the same copy of the software on another computer whether it's on your home network or halfway across the world and preferably, each node with your computer sw copy will be enabled for mining so each of the node has a chance to produce a new block
Good luck and hope your blockchain is successful