How to adapt small Dobsonian to use with a tripod?
First, a tripod won't help you point to a particular location in the sky.  For that you would need a correctly-aligned equatorial mount with setting circles, or a mount with digital encoders (you can get these for dobsonians) that when correctly configured can convert the telescopes position to a position on the celestial sphere.

It is possible to convert a dobsonian to a different kind of mounting.  If your telescope doesn't already have a tripod bracket, you would probably need to buy tube rings such as these, and put one on either side of the circles on the sides of the tube that sit in the rocker box, so that the center of gravity of the scope was between the rings.  Then you'd probably need a plate connecting the rings and providing a mount point between them that you could attach to a tripod or a more complex mount (like an equatorial).

My suspicion is that rather than trying to adapt the dobsonian to a different mount, you'd be better served either by buying after-market digital encoders for your dobsonian, or just getting a whole new telescope with the kind of mounting you want.