A basic paragraph consists of at least five sentences:
topic sentence (promise sentence): the topic, briefly stated, that you promise to write about (remember not to use the words 'I' or "In this paragraph..")
3 (min.) support sentences (keeping your promise): details about your promise
concluding sentence (reminding reader about your promise): restating the topic you just wrote about
example
I have three boys. My oldest boy, Robert, works and goes to school in Kamloops. My middle son, Andrew, goes to school in Victoria. My youngest son, Jonathan, works in Victoria. These are my three very busy, wonderful sons.