There are two ways to move cash money to lightning on strike. One, as you mentioned, is to buy bitcoin. You can’t send it directly to lightning though, as the bitcoin is held on chain. Therefore, you send it to your lightning nodes on chain wallet, and open a channel with it. If you don’t have your own node, you need to start one for this option. If you’d like to send lightning bitcoin directly to a custodial service like WoS, you’ll need to produce a lightning invoice within that service, and then scan it from the home page in strike using the QR code reader top right. Instead of “buying” bitcoin, and then sending it, you simply pay the lightning invoice and strike will send your sats over lightning network to your other wallet service