How to setup those tropical fish tanks? I'm gonna provide you a simple guide.
Shopping list:

• tank special mat to put under the tank (so it won't move)
• lightning equipped cover
• filter
• sand or gravel
• some plants for start

Optional:

• Heater (if you want to keep fishes or plants that like higher temps)
• Solid case designed for aquariums (if you don't have something solid to place it already)
• decorations like: rocks, caves, stones, roots

Fish tank set up guide: Put the mat on a solid case then you can place the tank on it.
Put the cover on top.
Make sure that you place a tank far from window, so that sun light won't operate on it.
Install the filter as it says in the manual.
Then start placing gravel.
On the back of your tank there should be 24-28 inches (8-9cm) and then sliding towards the front where you should have something like 16 inches (4cm) of it.
You may want to put some decorations inside but don't be silly buying any divers or boats.
Then pour gently water till you reach like 9-15 inches (3-5cm) so you can start planting.
Then you can fill the rest of the tank with water, launch your filter + lightning.
You should now wait for about 2-3 weeks in this time your new aquarium will maturate, after that you can go on and buy fish.
This is just a simple guide that will get you started with your first tank, then you can expand your knowledge on more advanced topics.