Shawn
In Chinese, actions are spoken in the order in which they must happen, first.
So your 1st English sentence would be ...
1. I leave work later (or afterwards), I go Starbucks drink (or buy) green tea, afterwards, I will go (or at) gym exercise
(the prepositions (to) and conjunction (and) we use in English are omitted. So as you can see, the sentence is structured in order of 1st action 1s.
.
finish work (action 1), then I will go or at what place buy (action 2) and finally, action three
person + at what time + at what place + do what thing <<< of course any of these can be omitted
Your 2nd sentence does not explicitly state where you were when the action took place
did you:
i at mall sent email to give him
or do you mean
while I was driving (walking/going) mall, at same time, sent email to give him
one final note:
you always have to be aware of where the action takes place because that will deteremine if the place words go before or after the verb
look at annabelle's sentence
我下班后去Starbucks买一杯绿茶,我也在健身房锻炼。
i leave work afterwards go starbucks buy cup of tea, i also at gym exercise
you have to be at work before you can leave work
you have to "go" starbucks before you can buy tea at starbucks
you have to be at gym before you can exercise at the gym