until now I have used Bootstrap for building my sites. I heard about Microsoft FAST web-controls, and I want to try it but there is no layout grid. How am I supposed to do layouting in MS FAST? I am no web designer, this is why I use bootstrap templates. I also use Aurelia as my framework of choice to build web apps.
The answer to how are you supposed to do layouting is "there is no how". It's up to you. What FAST offers is some building blocks (@microsoft/fast-foundation) to allow you to implement your custom design system. So you could go on using bootstrap or turn to material design or another choice.
Here's the link to the info supporting this answer: https://www.fast.design/docs/introduction/#how-can-fast-help-me
Regards.