Mick
If Daisy has profuse feathering on her front legs - the thinners can be used to thin it out. Only trim the length if you need to. You can take the ends off - lightly - to remove any unsightly straggles.
You can also thin the chest furnishings if they are very thick. It's really down to you and the look you want and how much hair you want to deal with. Scour the web for pictures of Cockers and find ones you like the look of then you know what you're aiming for. Keep that picture to hand when trimming - it'll help you picture how it looks against your girl.
The main thing is to snip once - brush step back and look again - you can take more off but you can't put it back on.!! We ALL wish we could at times.
Use the thinners on her throat to trim the hair close to the skin - this can be difficult and you have to be very careful not to catch the dogs throat - coz it hurts
Have you got some straight scissors? You'll need them to do the feet. Cut away all the excess hair under the paws so that it is level with the pads. Don't go in between the pads. When she is standing - take your straight scissors and cut vertically down against the side and front of her paw to cut away all the hair that sticks out.
It is not easy and takes time to learn. You will make mistakes - honest we all do.
I have some ifno'n on my web-site about trimming and also a link to another site that gives some really good pointers.
A word of warning about the video. I have it - it's not bad but doesn't really deal with a dog that has a lot of coat or one that wriggles and has ticklish feet
hth a bit anyway