You go to template and click custom then you just change anything that you want changed. I changed the background from that blown colour the watermark template comes with to a simple white colour because I prefer things to be simple that over complicated and over designed.
So for my header I used an app called PicCollage. Pic Collage is a life saver, I'm not going to lie its the best place to make headers. I made my simple header from there and I make my blog post header from there as well.
When you are done with designing your header all you do is screenshot it then crop it to a small size like this and save it.
Then you go to Layout, Header and where it says header you click the blue writing towards the bottom right. It should then look like this..
Then you tick the boxes I have ticked and you add the header. When its added you will notice it looks sort of grey and if you didn't notice you will when you view your blog after. To solve that you need to go to you're google+ settings ( Here ) and click on photo then untick this box and re-add the header again.
This should be the final look with the header that you designed it the way you wanted it. You could easily go back to layout but go to the right and click on Add Gadgets and it comes up with a list on things too add. Add anything you want too; I sometimes use the poll gadget and I ask " What Should My Next Blog Post be About? " and I give a few options and people vote and you do the highest vote. All you need to do is give it time and learn new things.
When I first started blogger my page looked nothing like this. If you want to see what it was like you click ( Here ). It took me ages to design my blog and at the time I wish I had help like this because I tried googling specific things but nothing really helped so I decided to do a quick and hopefully easy post to help new bloggers.
Hope you enjoyed and Thanks for reading