This is a pretty simple and weak ritual, and there are tonnes of variations you can use! Typically this is used when you wake up and want to start the day, but it can also be used in spell clean-up, preparation for spells or tarot readings, or just if you want to cleanse some negativity. Here’s a way to do it:

Open the windows to your bedroom and visualize all the negativity going out with the wind and say three times:

“My will is my shield, only the good may pass”

Then take your blanket and shake it out three times and say (also three times):

“You who cause me harm are not welcome here”

Ring a bell (or bells in a multiple of three) over where you slept, the windowsill, and wherever else yo deem needs purification and say:

"The sound is my barrier, my mind it's lifeline"

If you don’t have a window you can just ring a bell three times or knock on the door or the walls, it’s a really flexible ritual, so do what feels right! Good Luck and happy crafting!