Unless you’re a time traveller (and therefore familiar with temporal paradoxes), you’ll be confused by sentences where the writer did not follow a logical progression in time (that skipped writing course at university would have helped now) and now covers too much temporal real estate in a single sentence—don’t you start doing this!
English has twelve tenses. Present tense is the only real tense—all the others are factors of our imagination. The best rule of thumb is to stick to the present tense as much as possible and make occasional forays to other tenses as needed. Don’t make time travellers of your readers by hiking them hither and yon through your temporal landscapes.