If you were magically sent back in time to a time period with primitive to no technology, how much could you make/create?

[BasicHumanUnit]

If you tried to do any kind of recreation of modern technology, you would probably be called some kind of evil heretic and summarily dismembered or tortured to death in some unimaginably horrible medieval torture device.

Humans can be very closed minded and just plain stupid.
Most of the great historic scientific minds we acknowledge today were chastised and ridiculed by their peers in their day.

 

[San Souci]

Imagine that you were magically sent back thousands of years. There are no grocery stores, no hardware stores....nothing. The primitive people of the time are making tools from rocks and bones. How much could you advance the technology of the day based on what you know having to basically start from scratch?

Lever. Pully. Wheel and Axle.