Let's start at the beginning. Assuming that you're using a 'normal' TV set (i.e. not one specifically designed to be used with Freesat), you can't receive anything by simply connecting a satellite dish to its aerial socket. You need a set-top box to go between the two.
Such a box can either be a 'generic' satellite receiver or a designated Freesat one. (A Sky box without a valid subscription associated with it with it acts as a generic satellite receiver).
A generic satellite receiver will get you all of the channels listed here:
https://en.wikipedia.org/wiki/List_of_free-to-air_channels_at_28%C2%B0E
A Freesat receiver is actually configured to receive just a
subset of that list of channels, as shown here:
https://www.freesat.co.uk/whats/full-channel-list/
(However if there's anything else from my first link which you wanted to receive via Freesat box you can manually configure it to do so). A Freesat box also gets you Freesat's electronic programme guide and easier access to 'red button' services.
Freeview is a separate system, owned and operated by the BBC, ITV, Channel 4, Sky and the transmitter owners, Arqiva. It's entirely terrestrial, so you can't get it (per se) via a satellite dish. However almost everything which is available on Freeview (plus more) is in my first link above anyway.
All of the foregoing assumes that your satellite dish is pointed at the Astra group of satellites, which is used by both Freesat and Sky. If, say, you've just moved into a house which was formerly occupied by a Polish family, they might have installed their satellite dish to point at one of the Hotbird satellites (so that they could watch Polish channels). You'd need to realign such a dish in order to receive the channels from my first link above.