This is guide for someone who is completely new to Bitcoin to get started as fast as possible, this is intended to be the easiest way
Install the Wallet of Satoshi app on your phone, you can use the following links:
Open the app, you will be greeted with the following screen:
It will ask for your email so you can recover your funds if you uninstall the app or install it on another device.
If you already have some Bitcoins on another wallet or exchange you can tap "Receive" and transfer your funds.
You can also buy Bitcoins directly on the wallet using a Credit Card, to do so tap on the three dots button on the top right corner and the following menu will open:
Tap "Buy Bitcoin" and the following page will open:
Select the amount you want to buy (in USD) (minimum of $30) and continue to the next form.
Now fill in your card details and tap "Buy Now", the amount you purchased in Bitcoin will be credit to your wallet in a few minutes.
With some Btcoins in your wallet you're ready to make payments with it.
When you select Bitcoin payments on websites, a window like in the image below will appear:
Select the "Lightning" whenever it is available as it will allow for instant payments without fees, tap "Send" on your wallet and scan the QR Code. If you have enough balance on your wallet, confirm the payment and it will be completed.