rocket thakshane gana danna aya dannava USA hadata giyapu eka
boruvak kiyala,
missile ato gena hadata yanava missile tika ivara vela karakilaa karakilaa
kohoma hari hadata giyaa kiyamuko hade idala enne flight ekeda
hadata yanna puluvan ennai bari, thakshane na. ehema nam
oya agaharu vage evata yavapu evath genna gannava mokada ehema karanna
tharam thakshanayak na, balagathu rusiyava vage ratavaluth dannava
amarikava kare boruvak kiyala namuth rocket thakshaneta abiyoga
karala eka boruvak kiyala un kiyanna giyena, uda balagena kela gahaa
ganna hoda nane
A rocket engine. But the trick is that the rocket stage that took off the moon only needed enough fuel to bring the Astronauts (and soil samples from the Moon) back to Lunar orbit, where the much more powerful command-service module (CSM) was waiting to bring them back to Earth. Also, the descent stage of the lunar lander acted as a sort of "launch station" and was left behind.
Also, it should be noted that there are many different types of rocket engines. The ones used to take off from Earth are very maintenance-intensive, because we can afford them like that. For example, they're powered by liquid oxygen and liquid hydrogen, which have to be stored so cold that they literally boil in the tanks and have to be replenished continuously during the countdown.
The kind of engine used in the Lunar ascent stage uses hypergolic fuel. This basically means storing two different chemicals that ignite on contact, then making them come into contact on purpose - they don't require an external ignition source, which removes a possible point of failure. Much easier to operate, but much less powerful than a liquid oxygen/hydrogen engine - but that's fine, because gravity is much weaker on the Moon.
They didn't need a rocket like they did on Earth since the gravity on the Moon is about 17% what it is here.
The astronauts would start in a lunar parking orbit in the CSM (Command Service Module) which the LM (Lunar Module) was attached to. When they were ready to explore the moon's surface, they climbed in the LM, detached from the CSM, and descended towards the moon using a descent stage on the LM.
After they were done, they used the descent stage as a launch pad, fired up the ascent engine, and then would rendezvous with the CSM. Once everyone was safely in the CSM (along with any samples they collected), they detached the LM and went home.