You can build a very large ship and accelerate it with Space Solar Power to some percentage of the speed of light out of the solar system. Store enough nuclear energy and reaction mass to slow it down once it reaches its destination. And that is how you get to another star in however many centuries it takes. A small group living their lives on the ship and providing future generations of passengers is the only option at present. The far more likely scenario is not only reversing aging giving human beings an indefinite lifespan, but also freezing them without damage. Star travelers would thus look forward to thousands of years in which to explore other worlds and since almost all of the transit time would be spent frozen, they would be alive tens of thousands of years after they left Earth. Artificial intellects would eventually create Starships capable of flying close to the speed of light using artificial small black holes. The time spent frozen would then only be a year or so at a time.
Exploration across these thousands of years would only be incidental to the common task of resurrecting all life and then ascending to a higher plane.
It can be done by using hydrogen/oxygen reusable rockets sending factory tooling to the Moon and building the components in lunar factories. It is the only real solution to climate change.