Use the simple past tense when you are talking about something that happened at one particular time in the past (i.e., the event began and ended in the past). Normally, there is a reference to past time (yesterday, last night, etc.):

--I knew your aunt when she was young.
--Yesterday, they bought a car.
--We rented a car last week.
--He saw the U.S. Capitol while he was in Washington.

For many verbs, just add the ending -ed to the verb to make it simple past:

borrow-->borrowed
close-->closed
open-->opened
cash --> cashed.

Here are some rules for making the simple past tense of regular verbs:

1. Verbs ending in -e, add -d (hope --> hoped)

2. Verbs ending in a vowel and a consonant:

A. For one-syllable verbs having a single vowel, double the consonant ending:

stop-->stopped
rob-->robbed

B. For one-syllable verbs having two vowels, just add -ed:

rain-->rained
dreamed-->dreamed (also, dreamt)

C. For two-syllable verbs, in which the first syllable is stressed, just add -ed:

listen-->listened

D. For two-syllable verbs, in which the second syllable is stressed, double the consonant ending as you did for 1. above:

prefer-->preferred
control -->controlled

3. Verbs ending in -y. If the -y is preceded by a vowel, keep the -y (enjoyed, prayed); if the -y is preceded by a consonant, change the -y to -i and add -ed:

try-->tried
study-->studied

4. Verbs ending in -ie, add -d:

die-->died

5. Verbs ending in two consonants, just add the ending -ed.
NOTE: For regular verbs the form of the simple past is also the form of the past participle!!