Store in your fridge and don?t fully seal the bag, your yeast likes to breathe, 1g of yeast has about 10 million single cells.
Use about double the weight to dried yeast recipes.
If you are doing a longer fermentation (go on) you can use a lesser amount as fresh yeast will multiply/double over 8 – 10 hours.
Make a ferment – about one third of your recipe with 10g of yeast per litre, allow to rise then store in fridge overnight. Add this to the rest of the dough with the rest of the yeast, then proceed like normal, the taste quality will be much greater and you are becoming a baker 🙂