~たら as a verb suffix has two basic functions: Expressing temporal antecedence, as basically a synonym for (possibly contraction from?) ~てから -- 「A[VERB]たらB」 means "A [VERB], then B". Expressing conditionality, similar to English "if" -- 「A[VERB]たらB」 means "if A [VERB], then B". You'll notice tha...