I'm currently downloading it but need to leave for work soon, so I won't get a chance to play it for another 12 hours However, reading up on it, it looks like you need to purchase a module before you can drop down to planets, moons etc (no the ship doesn't automatically come equipped with it like we thought). Also, not every station sells the SRV, apparently the founders world doesn't have it. They say a system called Asellus Primus has everything you need.

Edit: Looks like the beta has it's first bug, some people can buy the PLS but not the SRV (giving an error Elite: Dangerous Horizons is needed to access this content), FDEV are looking into it.