Do I just mix the cement with water or do I need to add some sand?
There are no instructions on the bag!



You want concrete not a mortar mix - use something like a 1:2:4 mix ....
i.e. 1 part cement, 2 parts sand, 4 parts chippings.

Mix dry first, then heap up and make a depression in middle, add some water,
and mix ... you should keep water low - just enough to make all parts of
the mix join together, the test is if you can squeeze it in your hand and it
will form a ball without falling apart, then it's about right - if water
squeezes out - it's too wet (add a bit of cement & sand to dry out)

(Or if you chop up and down with a shovel it will keep the shapes made
without slumping back.)

Pack into the hole - ram down with an offcut of wood and then later in the
day water in with a watering can. - job done.

If you use a wet mix it will be difficult to keep post upright, and there is
no need for loads of water.

But for a swing none of the above is critical.

Rick