Or go to Uniswap and click "Select a currency" and enter this contract address into the search field, and you should be able to find Space Doge.
Open your Metamask wallet extension and and click "connect" on the upper left.
Your wallet should now be connected to Uniswap, and your Ethereum balance should show up in Uniswap.
Before making the trade in Uniswap, click on the settings icon , and in the 4th box under slippage tolerance, set it to 5%.
Then click max next to ETH and click swap.
You will see that it will not process the trade due to insufficient funds to cover gas fees. You can either try to calculate what the gas fees would be in Ethereum or do it the easy way as shown below.
Just keep subtracting from the Ethereum amount in order to leave enough for gas fees. For example: if you have 0.56 Ethereum, try to only trade 0.55 Ethereum then click swap again. Keep lowering the Ethereum amount in small increments until the trade is successful.