Before we talk about brushes I will just quickly mention gummed tape.
The tape I am talking about is what you will need to stick your wet watercolour paper to your board. Quite obviously ordinary sticky tape or masking tape won't do, as this would just peel away from the damp paper. You need the kind which needs to be wetted to make it sticky. I am mentioning this as someone told me that they weren't quite sure what tape I meant. I have found this site by googling it - http://www.artdiscount.co.uk/acatalog/Brown_Gummed_Paper_Tape.html and it does show what I mean. I haven't used this store personally as I buy mine from my framer.
Okay, back to brushes. A very difficult subject for me to be able to make any recommendations to you. Artists vary widely in the sort of brushes which they like and use. For my own work, I mainly use a size 3 pure sable. I like two makes in particular - Rosemary & Co and Premier Brush (www.premierbrush.co.uk) - perhaps my favourite of these is the P33? Maybe and then maybe not - each brush varies quite a lot and I have to spend a long time in my local art shop trying them out to find out which one suits my needs. In any art shop worth its name you will find a small pot of water beside the brushes. This isn't for thirsty tiny people, but it is for you to try out the brushes in. When I buy my brushes, I am looking for several attributes. Firstly I need the brush to hold a reasonable amount of paint - bearing in mind that due to the small size, this is still a very small quantity. It must be springy and not flop when wet. When I say springy, I mean that when you press the brush against the paper and then lift it off, it springs back into shape. When my brush is wet, I like it to come to a fine point with no odd little hairs sticking out further than the rest. But now comes my own peculiar brush requirement! When I press the brush down against the back of my nail, I want the brush to fan out so that the bristles make a straight edge. The photo above shows what I mean. I use the brush like this to make the fine coat texture in my paintings. Unfortunately, due to the way I use these brushes, they only last for about one or two paintings before I need to use a new one as they become blunt and therefore the coat texture in my paintings would become coarse unless I changed the brush for a fresh one. I have only found sable to meet my needs with the exception of the brush I use for laying in the backgrounds which is a Daler Rowney Dalon D88 1". I also have a very old and worn half inch brush which I use for scrubbing out areas of colour (or should I say reducing areas of colour as you can never get back to the white paper once it is painted on). Of course if you looked in my paint box, you would find it full of all sort of brushes which I have collected over the years and which have been discarded but not completely, as you never know when I might need it!!
So, you have your paper on your board, you have your paints and now your brushes. All you need to start your painting is some clean water and a piece of kitchen roll to wipe your brush on, and you're off!
I really would suggest that you spend more of your time finding out what the paints do, rather than rushing in with painting a picture. I only say this as I don't want you to become discouraged. It is so easy to start full of enthusiasm and quickly come to the conclusion that you can't paint, when had you only taken things more slowly, you would have seen that after all you can paint! It isn't only being an 'artist' that makes you able to paint, it's much more about learning the skill of how the paints work which will enable you to produce paintings you will be proud of. Everyone can paint - we all just need confidence and practice. Also, don't worry about what you paint. Paint what intrigues and satisfies you. Don't worry if it isn't fashionable or if the cognoscenti would turn their noses up at it - if you like it, it's ART!!