To dwell in the here and now does not mean you never think about the past or responsibly plan for the futurre. The idea is simply not to allow yourself to get lost in regrets about hte past or worriees about hte future. i fyou are firmly grounded in the present moment, the past can be an object of inquiry, the object of your mindfulness and concentration. you can attain many insights by looking into the past. But you are still grounded in the present moment.