Place your pulp in the first bowl and pour the hot water over it.
Leave to soak for 5 minutes, mashing with a fork halfway through, to loosen the pulp.
At the end of 5 minutes, mash it up well with your fingers. I find that the water, by this stage, isn't too hot to handle. If you do, add a little cold water (or water from the tap) to cool it down. Don't worry about the dilution if it's going to be cooked.If it's going in a chutney, then perhaps, let your boiling water cool down for 5 minutes, then soak the pulp for 10 minutes. Basically, the hotter the water, the less time it needs to soak.
Strain your tamarind mix through your sieve or strainer, pushing down on the pulp in the strainer.You don't want your sieve too fine, as you won't get the essence of the tamarind juice which will be too big to go through.You could also just strain it straight onto your recipe. My granny wouldn't even bother with a strainer, she'd just get the pulp and big pieces out, and drop the rest into the dish she was cooking. I do this very often too.
Any leftover can be kept, covered, in the fridge for a week.