Step 1: Moshi-moshi?

A: "Moshi-moshi, Tanaka-san no otaku desuka?" 
(Hello. Is this Tanaka residence?) 
B: "Hai, so desu." 
(Yes, it is.) 
Let me explain these sentences in detail. 

"moshi-moshi"(hello) -Please be careful.  "moshi-moshi" is only used in a phone conversation.  So, "Hello" as a greeting in Japanese is "kon-nichi-wa".  If you would like to review this, please go back to lesson 1. 
"-san" is a general title.  It can be used for both men and women.  For kids, you can use "-chan", while you can use "-sama" for politer title. 
"no"(particle "no") indicates possession.  It usually follows a name of people including person, organization, and corporation.  "no" is also in lesson 2 if you wish to review. 
"otaku"(residence) -"o"indicates politeness, and can be added in front of any nouns but name.  "taku" means residence or house.  "desuka" -"desu" is the verb which means "is" in English. "ka" is used for question sentences. In other words, if you put "ka" after "desu", you are asking a question.  "desuka" is also shown on lesson 6. 
"so"(so) -Surprisingly, "so" has a kind of similar meaning of 'so' in English.  However, it is difficult for me to explain what "so" exactly means, because there is no exact meaning.  In this example above, "so desu" means 'yes'.  Thus, you can omit either "hai" or "so desu" in the example. 

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Step 2: *** desu ga?
A: "(Watashi wa) Dave Letterman desu ga, go-shu-jin wa ira-sshai-masu ka?" 
([I am] Dave Letterman.  Is your husband there?) 
B: "Ima imasen. " 
(He is not here right now.) 

* Note: B is Mrs. Tanaka, and A(Dave Letterman) wants to talk to Mr. Tanaka. 

Sentence in detail:

"ga" is a conjunction, but it does not have any meaning in this example. 
"go-shu-jin" (husband) -Please be careful. "go-shu-jin" cannot be used for yourself (if you are a husband) or your husband.  In other words, "go-shu-jin" can be used to refer to other people's husband.   For example (pretend you are a wife), you CANNOT say "(Kare ga) Watashi no go-shu-jin desu."[means '(He is) my husband.].  Instead, "(Karega) Watashi no otto desu." ["otto" can be used if you refer to your husband.] 
For other people's husband   -use "go-shu-jin" 
For your husband                    -use "otto" 
For other people's wife            -use "oku-san" or "oku-sama"(a politer word) 
For your wife                             -use "ka-nai" 
"wa" -see lesson 2 
"ira-sshai-masu ka" (Is there...?) -This is a polite expression, but it is commonly used.  "imasu ka" is used by kids.  Remember "ka" is used for question sentences. In other words, if you put "ka" after "desu", you are asking a question. "ka" is also shown in lesson 4. 
"ima" (right now) 
                For your information, here is some time words. 
"ki-noh" (yesterday) 
"kyoh" (today) 
"sa-kki"(a short while ago) 
"su-gu" (soon) 
"ashita" (tomorrow)

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Step 3: Nanji goro...?
This is something you should feel familiar with.  Remember in lesson 4, you learn to say "what time it is?" 

A: "Nan-ji goro okae-ri ni nari masu ka?" 
(What time will he come back?) 
B: "Ku-ji goro kari masu." 
(He will be back around 9 o'clock.) 

* Note: B is Mrs. Tanaka, and A(Dave Letterman) wants to talk to Mr. Tanaka. 

"Nan-ji goro oka-eri ni nari masu ka?" 
"nan-ji"(what time?) -see lesson 4. 
"goro"(around/about) 
"oka-eri ni nari masu ka" ([he or she] will be back) -As you might notice, "o"indicates politeness, and "ka" is used for question sentences. 
"Kaeri masu" (come back) -"kaeri masu" is a casual form of "oka-eri ni nari masu"  One thing you should keep in mind is that Japanese people do NOT use polite language when they refer to someone in close relationship including family, relatives, and close friends. 

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Step 4: Shi-tsu-rei shimasu.

A: "Wakari mashita.  Ato-de mata kake masu.  Shi-tsu-rei shimasu." 
(I see. I will call him later.  Good-bye.) 
B: "Shitsu-rei shimasu." 
(Good-bye.) 
Let me explain these sentences in detail. 

"wakari mashita" (I understand) 
"ato-de" (later) 
"mata" (again) 
"kake masu" (call) 
"denwa o kakeru" -means 'call someone by phone'.  "denwa" is 'telephone'. 
"shi-tsu-rei shimasu" (Good-bye) -You can also use "sayou-nara" in lesson 1. 

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Step 5: Quiz
Try to say the following sentences in Japanese!  Answer questions ALOUD. If you can, try with you partner just like actual conversation. Good luck! 
  
"Hello."      Hint: This is not a greeting   
"Is this Clinton residence?" 
"This is [put your name here]." 
"Is there Mrs. Clinton?" 
"She is not here right now." 
"What time will she come back?" 
"She will be back around 12pm." 
"I see. I will call her later.  Good-bye." 
"Good-bye." 
Note: Mr. Clinton answers your call, but you want to talk to Mrs. Clinton. 
If you are done, check your answers with my answers below!  Hey, NO peeking!!!  Do NOT see this before you try the quiz first! 

Answers 

"Moshi-moshi" 
"Clinton-san no otaku desuka?" 
"[put your name here] desuga..." 
"Oku-san wa ira-sshai masuka?"  -->Remember "oku-san"?  See Step 2 
"Ima imasen" 
"Nan-ji goro oka-eri ni nari masu ka?" 
"Gogo ju-ni-ji goro kaeri masu." --> Remember "gogo" and "ju-ni-ji"?  For your review, refer back to lesson 4. 
"Wakari mashita. Ato-de mata kake masu.  Shi-tsu-rei shimasu." 
"Shi-tsu-rei shimasu." 
Since we just finish the normal phone conversation, you might wonder how we can say, "you have the wrong number."  Let's try it before we wrap up this lesson! 

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Step 6: You have the wrong number.
Let's take a look at the following sentences! 
A: "Moshi-moshi. Cosby-san no otaku desuka?" 
(Hello. Is this Cosby residence?) 
B: "I-i-e, chigai masu." 
(No, you have the wrong number.) 
A: "Domo sumi masen." 
(I am sorry.) 
B: "I-i-e, do itashi mashite." 
(That's quite all right.)