You cannot currently make a real, practical time machine with known science
Use Einstein’s relativity to study time dilation
Travel at speeds near the speed of light to move into the future faster than others
Use strong gravitational fields to slow time relative to distant observers
Build a spacecraft capable of extreme acceleration and radiation shielding
Generate or access a stable wormhole if one could ever be created
Keep one end of the wormhole near a massive object or at high velocity
Maintain wormhole stability with hypothetical exotic matter
Prevent collapse of the wormhole with negative energy conditions
Control synchronization between the two wormhole mouths
Limit paradoxes by applying consistent-causality rules
Use quantum gravity research to explore whether backward time travel is possible
Accept that backward time travel remains speculative and unproven