sequence of actions in the present (first - then, after that)
instructions
things in general
after special verbs
action finished in the past (single or repeated)
series of completed actions in the past
2. Signal words
Simple Present*
Simple Past
always
often
usually
sometimes
seldom
never
every day
every week
every year
on Mondays
yesterday
last week
a month ago
in 2018
this morning
* Signal words of the Simple Present can also be used in the Simple Past. This happens when you want to say that you did something regularly in the past (here: last week).