According to

대로: doing it exactly the way something says

대로 means "according to", "just as", or "the way that". It's one of the more useful things to learn early, because it turns up constantly in instructions, requests and complaints.

With a noun

Attach it straight to the noun. Nothing changes for consonants or vowels.

• 계획대로 하세요. (gyehoek-daero haseyo) — "Do it according to the plan."
• 약속대로 왔어요. (yaksok-daero wasseoyo) — "I came as promised."
• 마음대로 하세요. (maeum-daero haseyo) — "Do as you like."

That last one is worth memorizing whole. 마음대로 literally reads "according to your heart" and it's everywhere in speech.

With a verb, and the tense matters

This is where 대로 gets interesting, because the verb ending in front of it changes the meaning.

~는 대로 (present) means "as soon as", or "in the way that it's happening":

• 도착하는 대로 전화할게요. (dochakaneun daero jeonhwahalgeyo) — "I'll call as soon as I arrive."

~(으)ㄴ 대로 (past) means "just as it was", "the way I did":

• 제가 본 대로 말할게요. (jega bon daero malhalgeyo) — "I'll tell you just as I saw it."

Same particle, and the tense of the verb in front decides whether you're talking about timing or about faithfulness to something.

대로 vs 처럼

Both get translated "like" or "as", and they aren't interchangeable.

• 대로 = following something exactly, as an instruction or a model.
• 처럼** = resembling something.

• 선생님이 말한 대로 했어요. (seonsaengnim-i malhan daero haesseoyo) — "I did it exactly as the teacher said." You followed the instruction.
• 선생님처럼 말했어요. (seonsaengnim-cheoreom malhaesseoyo) — "I spoke like the teacher." You resembled them.

The first is compliance. The second is similarity. Swap them and the sentence still parses, which is exactly why the mistake survives so long.

The spacing rule

With a noun, 대로 attaches with no space: 계획대로.

With a verb, it takes a space: 본 대로, 하는 대로.

That's because after a verb it's working as a bound noun rather than a particle. Korean spelling rules follow the grammar here, and getting it wrong is a very visible mistake in writing.