Bristol is fortunate enough to have a Lego shop. There are so many wonderful kits to chose from and helpful staff.
If you are as old as me you may have been lucky to have had one of the first kits. In a wooden box with separate compartments. I think that mine had a mixture of red and white bricks, fairly basic shapes but it also had some slopes - used for roofs and some basic windows and doors. So it was imagination that was the main requirement there weren't detailed instructions.
Now there are kits to build specific models with some alarming prices!