Knitette

I'd like to make my darling SIL a Tumbling Blocks quilt for Christmas. I saw a video on this ages ago where two strips were joined and cut at an angle and joined. I plan to use three shades of blue to get the effect.

However, I've been searching for a simple pattern and have come across ones that speak about 'setting in' and Y-blocks?? What is that and will I need to do it?

I need a pattern that tells me how much fabric I'll need in each colour and the finished size - around a throw size would be great. (I'm not very experienced but can follow a pattern - just, lol).

Can anyone please point me in the direction of a simple pattern? (Happy to buy this).

Also, is there anything else I should know before I start?
Thank you!