Hi Kath and welcome to TFF!
You are really, really lucky to have posted here just prior to heading out to buy fish! Don't do it! Your info is wrong. A new tank setup is not ready for fish. By searching and finding a tropical fish hobbyist site like this you are going to hear some potentially confusing things, but its going to be the "real" stuff and should save you a lot of grief in the long run!
So many places to start!... The heart of all that equipment you are setting up is the filter, that is the key thing that beginners need to learn about. When a local fish shop (LFS) sells you a filter, what they never tell you is that its just a kit of raw hardware and even if you follow instructions and put it together its still not really functioning (can you believe that?)
The problem is that to make the filter fully functional takes some fairly arcane hobbyist knowledge and quite a lot of time and patience. Time and patience are things that will drive customers right back out the door, so its not surprising that the LFS is not in the habit of calling this sort of thing to your attention.
Filters have three functions: Mechanical filtration (the obvious catching of particles and debris which is the only thing most beginners think a filter is for,) Chemical filtration (which is optional and not needed unless you have a problem!) and finally, Biological filtration (which is the one most beginners have never heard of and which is a core bit of magic for the hobby!) All the media (sponges, ceramic rings, ceramic gravel, carbon, bioballs, floss etc.) overlap in their ability to do multiple of these functions, but each is best at one or another usually.
So let's get right to the magic! Biological filtration is one of the wonders of the world and it goes on all around us in nature. In the case of waterlife, here's a bit of the basics: Unlike us humans giving off only CO2 when we exhale, fish gills give off -ammonia- (as well as CO2) when they "ventilate." Fish waste, excess fish food and plant debris also turn into ammonia in an aquarium. In nature, this ammonia is flushed away by millions of gallons of fresh water. In your aquarium it builds up quickly.
Ammonia, even in small amounts causes permanent gill damage, shortens a fishes life and can cause death. In a biological, or "bio" filter, we grow a specific species of bacteria that likes to *eat* ammonia and turn it into nitrite(NO2). Nitrite(NO2), even in small amounts, damages the hemoglobin molecules in fish blood, causing suffocation, and permanent nerve damage, leading to shortened lives or death. In our biofilter we also attempt to grow a second specific species of bacteria that likes to (you guess it) *eat* nitrite(NO2) and it turns that into nitrate(NO3), which is not nearly so nasty and can be removed with weekly water changes.
This is the magic of the "biofilter," a concept that's been understood by scientists for many decades but is little appreciated by the average person walking into their LFS. Its truly a fascinating subject and understanding it as part of the "Nitrogen Cycle" of nature makes it still more interesting! Now, what does this mean for you?
Well, ever since the early 1980's a new technique has developed in the hobby whereby you can obtain and use "pure household ammonia" that's normally used as a cheap household cleaner, and "fishlessly cycle" your aquarium filter to grow the 2 needed bacterial species prior to introducing your new wet pets. Fishless Cycling is a big pain. Its a bit tricky to understand and it can take a long time. But it saves the lives of many fish and its one heck of a lot easier than keeping fish alive when you've obtained them without knowing about cycling.
What you do is put ammonia in the tank in a very controlled way, without fish of course, and then you test once and then later twice a day and base your actions on your test results day after day. It takes roughly between 3 and 6 weeks usually or occasionally longer if mistakes happen, but in the end your filter is functional and ready for fish and the water they are introduced to is pristine and a new home that they will love and flourish in.
Its obvious that I think fishless cycling is a "good thing." Its a good pathway for the average beginner who wants a first freshwater community tank and is more focused on fish than plants. There are a number of major branches in the hobby, biotopes and planted tanks being among them and fishless cycling is not always the choice of all these branches but hopefully you fall into the average freshwater community beginner and will be interested in fishless cycling.
Our Beginner Resource Center has articles that cover the the nitrogen cycle, tank startup and of course our working article that lays out the steps of fishless cycling, written by rdd1952. You can document your fishless cycle right here in your beginner's thread and the members will follow along and give pointers and answer questions.
Sorry for all the many paragraphs but beginners have told me these little bits are nice to come back to when they are learning, so here's hoping this isn't all old news to you...
~~waterdrop~~
Hi all , newbie I promise I will be reading up on keeping tropical fish as soon as I can, but can I please ask the following questions. I have just bought a 2ft tank last weekend and we have so far put in gravel, a few decorations pump, thermometer all that came with the starter kit, we have followed the manual so far we have treated the water as directed then again after 4 days as directed but the water is cloudy, having said that I have put in some bark but did clean it first but understand that this can make the water a bit cloudy. Is this normal and safe to add the fish which I hope to be able to buy at the weekend, the temperature is correct. 
