There are alot of tenses used to express actions in the past.  
 French imperfect conjugations are very easy. Drop the -ons ending from the present indicative nous form of the verb and adding the imperfect endings.

The imperfect "je mangeais" translates to the English imperfect "I was eating" while the passe compose "j'ai mangé" literally translates to the English present perfect "I have eaten" but can also be translated as the English simple past "I ate" or the emphatic past "I did eat".

The imperfect describes past situations whilst the passe compose narrates specific events, then in some cases the imperfect can can be put for an event WITH the passe compose.

The imperfect describes an action that was not completed. Such as: J'allais en France. - I was going to France. The imperfect is also used for repeated actions, or things that have happened an unknown number of times.  Such as:  Je visitais souvent le Louvre. - I often visited the Louvre.

The passe compose talks about a single event, or one that has happened a specifified number of times. Such as: J'ai voyagé en France l'année dernière. - I traveled in France last year. or J'ai visité le Louvre trois fois. - I've visited the Louvre three times.

The Imperfect describes a mental or physical state of being.  Such as: J'avais peur des chiens. - I was afraid of dogs.

The imperfect and passe compose sometimes go together: the imperfect provides a description or background information, to set a scene, or to explain what was happening (past tense of "be" + verb with -ing usually indicates this) when something (expressed with the passé composé) interrupted.

French imperfect conjugations are very easy. Drop the -ons ending from the present indicative nous form of the verb and adding the imperfect endings.

You add the imperfect endings to this stem: French Imperfect Endings
Pronoun      Ending     Parler          Finir         Etudier     Manger       Etre
je (j')               - ais              parlais           finissais        etudiais      mangais         etais
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                   -aient            parlaient        finissaient    étudiaient   mangeaient   étaient

Know that je, tu, and ils forms of the imperfect are pronounced the same way, even though they are spelled differently.
 
The imperfect of all verbs, except for etre, is formed the same way:

Avoir      nous avons --> j'avais
Commencer   nous commencons --> je commencais
Faire   nous faisons --> je faisais
Manger   nous mangeons --> je mangeais
Croire   nous croyons --> je croyais

Know the form of etre:

j'étais
tu étais
il était
nous étions
vous étiez
ils étaient

When typing in french you need to know how to put accents in, this is a few ways how to do that:

One way to get French accents on to your keyboard is to hold the ALT key and type in a four-digit code. One other way is go into control panel and change your keyboard to French-Canadian. Then you press ` (left of 1) and then the vowel after to get the grave accent. To get the aigu accent type ' (single quote) and then e. For the cedilla, type ' (single quote) and then c. Get the circonflexe by typing ^ (shift+6) and then e. And get the tréma by pressing " and then o. Another way to get accents is toupload Google Chrome! Once you get it, download the "Accents Plus" app on the Google Chrome home page.  The app sits in the top right corner of your screen.  You place your cursor over the kind of accent you need and it will show you what keys you need to press to get the accent. Usually, to hold two keys.