Improve the README a little bit

README.md

@@ -1,3 +1,20 @@
 # curriculum-vitae
 
 Charlotte's CV (in Typst)
+
+## Building
+
+- Install [Typst](https://typst.app/docs/) (you can `cargo install --git ...`)
+- `typst compile cv.typ`
+
+## Writing your own CV
+
+You can use `layout.typ` to get the same CV header layout that I have.
+You may want to change the accent color.
+
+The column layout is made in-document with a `grid` container per page,
+so you can look at `cv.typ` for examples.
+(using `#set page(columns: 2)` doesn't let you have unequal column widths)
+
+Icon SVGs are downloaded from [Font Awesome 6](https://fontawesome.com/) and
+cleaned up. Some paths have a `fill` attribute manually added with the accent color.