well, if you want to make an indoor burrow you have a few options.
1, buy a large drain pipe (think thats what its called) big enough for your tort to fit through. completely bury it with dirt like a dirt tunnel leaving one opening exposed. I've seen this done for Russians.
2, use a cinderblock and some of the caps to make a cave. Again pile the dirt up and over the burrow so the tort can be inside or walk on top. Member Kameya uses these and created a whole thread on how to build them.
3, you could use a large tupperware turned upside down with a hole cut out for the door. bury this in dirt for a nice humid hide/burrow...
I use a powerade bottle with both ends cut off and a slit up the midle in case an emergency extraction becomes necesary. I have also heard that 6 inch pvc cut at an angle and buried works pretty good. My little ones never used theirs so I gave it to the box turtles and they fight over it. LOL..
You don't need a burrow indoors. Burrows are for escaping the above ground temperature extremes. Just use an upside down dish washing tub with a door hole just big enough the tortoise indoors. This will give him a humid hide within the humid closed closed chamber.
If you want to do it anyway, go ahead and have fun with it.
Do you know what a plastic shoe box looks like? Or a clear tupperware you put your leftover dinner in?
Picture that with no lid. Turn it upside down so the "lid less" top sits on the dirt. Now take scissors and cut out a square your tortoise can walk through.
I can't link to pictures right now...can someone help him out and post a photo??