Besides mining, crafting and hiding at night. What else is their to do? How you go fight the ghost and dragon
to get to 'The End', and the dragon, you'll need to find a Stronghold, and repair the End Portal
to find a Stronghold, you're gonna need to get lucky exploring underground, or use an Eye of the Ender. I'll let you do your googles to find out how to do all that
but in general you'll need some kind of home base. make a bed, which will be your spawn point. store your valuables, so you won't lose too much if/when you die. mine deep to get good stuff, like gold and diamond, to craft the best gear. learn to navigate and explore without getting lost. I usually mark my route with torches. you also want to use a lot of torches underground, because keeping an area lit will stop baddies from spawning there
you're gonna want a strong foundation of good gear, special ores, and knowledge of your area, before you even think about trying to get to The End