Putting up a shed

I've been given a shed!  Isn't it funny, the things we get excited about as we age.  anyway. How do I fix it to the ground? The shed is 6 x 4'. I have a hard standing area at the top of the plot which is 10 x 6'. There are obvious bits at the corners of this concrete which were presumably for four posts to be driven into the earth, to fix the shed to and stop it blowing over?? Shall I use two of these - how long should the posts be above the ground to make it safe?

The shed has a very heavy base. Does it strictly need securing to the ground?

if the shed is a good weight then unless your putting it in a very windy place it should be ok none of mine have ever mood ,but if you possibly can get a cpl of rawbolts or 4" screws through the floor and into the concrete then you will feel safer ,because they are quite high . or as you said some posts knocke far enough into the ground and  screwed the shed into the posts ,whatever you decide well done phil

Mine sits on paving slabs. It's so full of stuff it can't blow away!

same here.
It was tipped over once by vandals, but I cured that by filling it with heavier "stuff" 

Look at this!  How lovely. Not finished with the roofing felt yet though.

.

Nice little shed - nice little fire too!