The imperfect is used to describe continuous, repeated, or habitual actions in the part. It is different from the passé composé because the passé composé is used to express actions that started and ended at a specific time in the past.
 
You should you the imperfect tense when using an action that was continued in the past (I was eating, they were doing, etc.)
     You use passé composé for describing a completed action in the past (I went, I saw, I did, etc.)

Pronoun                Ending               Parler                    Finir                     Etudier                     Manger                Etre
     je (j')                        -ais                   parlais                finissais                étudiais                mangeais            étais                                  
     tu                             -ais                   parlais                finissais                étudiais                mangeais             étais
     il                               -ait                    parlait                 finissait                  étudiait                 mangeait              était
     nous                        -ions                parlions              finissions             étudiions             mangions            étions
     vous                        -iez                    parliez                finissiez                 étudiiez                 mangiez               étiez
     ils/elles                  -aient                parlaient             finissaient            étudiaient             mangeaient         étaient

The imperfect of all verbs, except for the verb etre, is formed the same way.
Avoir -  j'avais, tu avais, il avait, nous avions, vous aviez, ils avaient  
Faire -  je faisais, tu faisais, il faisait, nous faisions, vous faisiez, ils faisaient
Etre - j'etais, tu etais, il etait, nous etions, vous etiez, ils, ils etaient
Aller - j'allais, tu allais, il allait, nous allions , vous alliez
Manger - je mangeais, tu mangeais, il mangeait, nous mangions, vous mangiez, ils mangeaient
Croire -  je croyais, tu croyais, il croyait, nous croyions, vous croyiez, ils croyaient

The first way is to use this chart and follow the instructions. Remember to use the number pad on the right hand side of the keyboard and to have your number lock on. 

The second way is to go into your control panel and change your keyboard to Canadian French. 

• To type an acute accent (é), type ´ (next to the right-hand shift key) and then e
• To type a grave accent (à, è, ù), type ' (apostrophe / single quote) then the vowel
• The circumflex ˆ and tréma ¨ are in the upper-right corner, side by side next to the enter key
• For ç, type ¸ (left of "enter") and then c

The final way is a website that allows you to copy and paste French accents without a French keyboard. You simply click on the accent you wish to use and copy and paste it onto your document. You could also save the website to your favorites bar to find it easier and quicker. I'm sure there are many other websites but the website shown here is http://french.typeit.org/