Various Blockchain explorers allow you to interact with a contract's entry points and visualize the resulting transactions. We will focus on two of them:
Better Call Dev: allows you to interact with an existing originated contract
SmartPy: allows you to originate a contract and interact with it
On https://better-call.dev/, you can find and interact with a contract. Search it with its address and then clic on interact and then on the fonction that you want to use on the right. You have access to a variety of wallet interaction possibilities.
Go to https://smartpy.io/ide and copy-paste the contract, you can run it and you will see the result in the Output panel.
Then scroll down on the right output to Contract and then click on Deploy Michelson Contract.
You will need to set the default parameters.
Go to https://smartpy.io/wallet.html, click on Faucet Account and Faucet Importer to import your key or create new ones on SmartPy.
Then go to Contracts and Link Contract to import the contract you just created.