Warning: English uses present tense in conditionals, even for future situations. Russian uses future.
   Љсли ћн придёт (future), ї емџ скажџ. If he comes (present!), I'll tell him.
Warning: English 'would' is used in situations where you can't use бы.
   Ћн сказђл, что придёт. He said he would (Lit. 'will') come.
   Ћн к нђм приходќл кђждый вљчер. He would (used to) come to our place every evening.
Warning: English 'if' is used in non-conditionals in the meaning 'whether'. Don't use љсли here.
   Ї не знђю: придёт ћн или нљт. (or: Ї не знђю, придёт ли ћн.) I don't know if (whether) he's coming or not.