How to colour digitally with layers

Hello my lovelies!

So I had a couple of people on deviantart request I do a tutorial on colouring!.. and I thought how fun. I'm terrible at explaining things however, so if anything remains unclear. Please feel free to let me know, and I will help further!
At first when I started drawing digitally, I was so stumped and confused by layers and how they worked, but you have done your research just like I did. Good on ya! *thumbs up to you* Hopefully this helps you out.. at least a little haha.

Okay. So to start things off... the most common programs for colouring are Photoshop (obviously) and what I use... Paint tool SAI (the best program ever). This tutorial will be for SAI, however its the same concept on photoshop.

Step 1: Open canvas to start drawing.. (Go to file > New)

Step 2: Now make a layer! by clicking the folded paper icon just above the circle here or (Layer > New layer)

Step 3: Now name your later whatever you want. Suggest you name it something you will remember! After than go ahead and draw your lineart ^^ I drew an ice-cream.. cause i'm craving it right now.. and its cute >u<!

Step 4: Okay so we now have our lineart completed on our first layer! Woo! 

So now we create a new layer, name it once again. 

Now as you can see when you colour on this layer, you are colouring is under your linart.. MAGIC!

Step 5: Okay now click the Magic wand tool  and click your "Linart" layer (The first layer you created) now click the area you want to colour with the magic wand tool. You will notice the part you have selected as turned blue!

Most of the time, the magic wand took won't select the whole area you want to colour.

To rectify this. Go the the select took! This is basicly a select brush. It allows you to brush over parts the magic want tool misses. Neat huh! ^7^

Now use this select took and brush over the bits the magic wand took misses, and wala you can start to colour! ^O^

Step 6: Now after your selected part has turned blue, go to your "Colour" layer (Second layer you created) and click it.

 Step 7: Use whatever tool you want. I suggest the Brush tool, but some like to use the bucket tool, and colour the selected area. You will notice that by what we have done, You have magically coloured only the selected layer, all neat and tidy. So this is the basics of the mystery that is layers!

 Thank you so much for reading, and again I'm sorry if this tutorial is sloppy xD I'm not good at explaining things! If you have any questions at all, please feel free to ask below in the comment section!
Oh and if you would like to suggest another tutorial you would like to see me do, please let me know ^^

bye bye everyone! Till next time! <3