How Do Meme Coins Using Another Established Coin’s Block-Chains Function

E.g. XRT uses the Ethereum Block-Chain, but what does that mean ?

Many people are frightened by the complexity of Crypto, huge charts and entire websites – dedicated to 'explaining' things for you in 'simple terms', when you know full-well someone somewhere in amongst all the confusing information is trying to sell you something.

So I have come here to ask.

It would be really great if someone could tell me, and probably any other amateurs, how one crypto-coin rides on another's "Block Chain. And how that can effect potential gains and losses, if the "Block Chain" owner (in this case Ethereum) is winning or losing, how would that affect XRT ?