To understand the process behind validator nodes, it is best to understand how Plian's Epochs are structured. Each Epoch is about 30 days in length but that is determined by the block times experienced. There are four important time periods within each Epoch.
The first time period from the beginning of the Epoch to 75% of the Epoch is where users can delegate their PI and Validators can apply as Candidate Nodes for users to delegate to.
The second time period is from 75% to 85% of the Epoch. This period is for all new validator nodes to submit their vote to become a validator in the next Epoch. During this time, you can no longer delegate PI or apply for candidacy.
The third time period is from 85% to 95% of the Epoch. This period is when all validator nodes that submitted their vote reveal their vote. During this time, no new votes are allowed, nor can users delegate or apply for candidacy.
The fourth and final time period is from 95% to 100% of the Epoch. At this time, all votes are locked in and the next Epoch's Validators are determined. Once the Epoch reaches 100%, the blockchain transitions to the next Epoch and the process starts over.
There are two different ways to use your PI to secure the network and get rewarded for doing so; delegating your PI to a Validator Candidate or staking your PI to your own Validator Node.
Delegating allows users to make the best use of their PI holdings to help secure the network without needing to operate their own node. This is done through the "Delegate" section in the PIWallet.
Staking allows users to operate their own nodes to either open them to delegations to gain more weight (Candidate Nodes) or to stake it individually with their own balance.
Rewards earned are divided evenly over the next 10 Epochs and unlocked when that Epoch is reached. This can be done via the "Extract Reward" function in the PIWallet.
PIWallet is the GUI wallet for use on all operating systems to interact with the Plian Network.
PMetamask is the Plian port of Metamask which is a web browser plugin that allows users to interact with the Plian Network.
If you are looking for a more in-depth look into what can be done with the Plian Network, look here. Includes guides on alternate installation instructions, RPC, and CLI options.