To use the Leather testnet desktop app go to the Github repo here to download the latest testnet version of the wallet, get the one for your Operating System (i.e. ending in .exe if you are using Windows):
Download the testnet wallet for your system from Github
This wallet will allow you to use a testnet address and funds for your wallet.
Getting testnet STX from the faucet:
You can get testnet STX via the button in the wallet:
Replace the address (ST21YNW6HP6Y3AX3WPF4J9HPYVJC0N77TBNDD6C33) in this link with your own testnet Stacks address.
If you need an amount large enough to stack on your own. You’ll want to adapt the last portion of the link to “true” instead of “false”. It will depend on the balance of the faucet address if the large amount can be send.
Getting testnet STX using the explorer sandbox and wallet extension
If the button and faucet URL are not working. Instead use the wallet extension. Do this by using the same seed phrase you used on the Desktop wallet on a Leather extension.
Choose the testnet network on the extension via the top right menu button.
Then use the explorer.hiro.so sandbox (1), select testnet (2, 3) here too, login with account one (4) (make sure the address starts with ST (that is a testnet address), visit the faucet page (5) and request STX (6):
Get STX testnet tokens from the Faucet on the Explorer Sandbox
How to get STX testnet tokens, video by Hiro:
Getting testnet STX using (a) the Hiro platform, (b) using the sandbox and by (c) directly calling the API.