Go to this site : https://htlc.me/, click on "Got it, I wrote it down", get your tBTC (not real BTC, "t" is for "testnet"). Then, you can go buy some fresh articles with Lightning transactions at https://yalls.org/ or some Caffe Latte at https://starblocks.acinq.co/ .
You need to copy the "payment request" of the site you want to buy from and paste it onto your htlc.me lightning wallet (in "send tBTC"). Once the transaction is confirmed on your wallet, you can go see on the site you bought from that the transaction has been confirmed instantly. All of this is still under development but lightning devs are doing an amazing job at it ! It's not that far down the road !
Be prepared for a long, long, road… developing in ethereum is a nightm…