What's a blockexplorer? 

A blockexplorer allows us to view the balances and transaction histories of all public addresses, as well as confirm if a transaction has been successfully added to a block. Examples of popular blockexplorers include: blockexplorer.com (for transactions on the Bitcoin, Bitcoin cash, and Zcash blockchains), etherscan.io (for ETH and ERC20 tokens), and neotracker.io (for NEO and NEP5 tokens)

How do I use a blockexplorer?

Let's say we sent ETH from an exchange to our Ethos Universal Wallet and now want to track this transaction. Since we are tracking ETH we will use etherscan.io. After sending the ETH, a transaction ID will be displayed or emailed to us by the exchange. If we copy the transaction ID (also written as Txid, Tx#, Txhash) and enter it into the search bar on etherscan.io, we will be brought to a page displaying information about the transaction. Here we can see if the transaction has been successful or has failed, who the sender and receiver are, when the transaction was processed, and more. 

If we forgot to record the transaction ID, or simply want to view our wallet transaction history, we can search any public address and view the transaction history (sent/received) and current balance.