Part-1a.-My-first-service.md

+# Using vim to create your first FastAPI service on IBM i.
+
+To insert text into a file using vim, press `i` on the keyboard, you are now in _insert mode_.
+
+Note the difference in the bottom left corner...
+
+![image](uploads/b06524b53cd8ce401e78df3610e798cf/image.png)
+
+## Type the the following code into **main.py**
+**(or not, be lazy, you know the chef has prepared something**...)
+
+```python
+from typing import Optional
+
+from fastapi import FastAPI
+
+app = FastAPI()
+
+@app.get("/")
+def read_root():
+    return {"Hello": "World"}
+
+
+@app.get("/items/{item_id}")
+def read_item(item_id: int, q: Optional[str] = None):
+    return {"item_id": item_id, "q": q}
+```
+
+## What does all that do?
+
+`app` is the name of our services entry-point, and is also used to annotate endpoints in our service.
+
+In this instance, the main endpoint `/` typically this is a file called _index.html_ on your web-server
+
+The endpoint `/items/{item_id}` uses _path-variables_ to input arguments to our function,\
+anything typed in curly braces, is copied into the function argument with the same name.
+
+You'll notice there is an additional argument in the function, called `q` this is a query-string variable,\
+anything not otherwise defined, is treated by FastAPI as a query-string argument.\
+Finally, this q argument, is defined as being optional, meaning the client is not required to provide it, and defaults to `None`.
+
+## Save changes, and run the service
+
+Leave _insert mode_, by pressing `Esc`,
+
+Save your changes by type `:w` \
+and exit vim by typing `:q`
+
+( This can be shorten to `:wq` )
+
+You are now back in the shell, where we will run this program using.
+
+
+[Proceed to the next page...](Part-1b.-Testing-my-first-service)
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