Merge pull request #219 from FourierFlows/ncc/patch

Adds clarification in Grids Docs section

Author: navidcy

docs/src/grids.md

@@ -15,6 +15,8 @@ end
 ```
 
 ```jldoctest
+julia> using FourierFlows
+
 julia> nx, Lx = 64, 2π;
 
 julia> grid = OneDGrid(nx, Lx)

docs/src/installation_instructions.md

@@ -9,6 +9,14 @@ julia>]
 (v1.4) pkg> instantiate
 ```
 
+Then call
+
+```julia
+julia> using FourierFlows
+```
+
+and you are good to go.
+
 You can update to the latest tagged release from the package manager via
 
 ```julia