Well, the hardest part of doing something yourself is to have the idea. After that, even if you are not very good at this kind of job you can learn and follow instructions. So the idea of making a table or a coffee table from an old tree log or stomp is the best start. The rest is just inspiration and work. Now the next important step is to find a tree log and clean it carefully, removing all materials like dirt and leaves from it. Then let it dry in the sun and try to adjust it a bit, so as to stand all alone and also be able to support the tabletop and whatever you will place on the table.
Then lacquer the log and let it dry again. You will have to find or make a tabletop in the meantime. Look at these pictures and choose the one you like. For example you can simply place a round or square sheet of thick glass and glue it or secure it to the log somehow. I personally do not like this combination because the log is totally natural and the glass is obtained by industrial processing, so they do not go together very well, but some people might like the idea.
Or maybe, and I think this is best, you can use a :slice: of a thicker log as tabletop and bolt it to the log and have a great table for outdoors. Or you can even use a round or square or even rectangular board as tabletop or place some more boards together as tabletop, as seen in the above pictures. It has a rustic look and it’s cheap.
Or finally take it very seriously and turn your work into a work of art. Use logs that look in an artistic way and create something unique. Hm, I still have a backup solution for the clumsy ones with a great taste : buy the item made by professionals. ($1500 for the coffee table in the last picture).