Smoking it or shooting it will be more likely to cause an overdose almost immediately compared to swallowing it which is slower and can lead to you throwing up the contents of the drug snorting is also an option and doesn't take anything special to do just a rolled up bill pretty simple.
If you live in an area where harm reduction services are available, you can go to your local hospital and request a glass pipe that has a bowl (this is for if you smoke it a torch or lighter will be needed for this option), or you can ask for an injection kit. You don't have to explain what you intend to use them for. They will likely provide you with a naloxone (Narcan) kit, which can reverse the effects of an opioid overdose. If you change your mind, having this option could save you, especially if the overdose isn't fatal. There are fentanyl testing strips at least where I live. All of this is free at the hospital except the lighter or torch is something you get at a gas station.
If you experience overdose but its not fatal, you will likely feel very nauseous and may vomit. I recommend doing this in the bathroom or near a bucket for convenience. It's common to feel extremely tired, so you might want to lay down a towel in the area where you plan to be for comfort. Keep some water and plain crackers or bread nearby, as these may help you feel a bit better if your attempt doesn't work as you will be throwing up and wont feel good.
This is from someone who has done fent.