I suggest learning a bit about carrier oils first and of course the Herbs you wish to work with.
* I only use Plant based Oils *
Some oils work well with certain herbs and some do not . This again is where personal preference comes into account as of course the Need because certain herbs help with certain things , such as Lavender works for Relaxation . So do some research and when you are ready and you have your herb/ herbs , and picked your carrier oil/ oils (yes you can blend your carrier oil) and of course a journal / notebook of some sort so you can write down what works ,what you mixed it with and when . This way you will have a Oils section for your Book of Shadows a personal recipe reference of contents and procedure .
When you have figured out what you want to create .
Take your dried herbs or fresh flowers what ever you are using and fill a jar ( any container with a tight fitting lid will do) I suggest to start small. I mean you don't want to fill up a quart jar making an oil infused concoction not knowing the outcome.
( START SMALL)
( I make fur baby treats and I have baby food jars some of you may have babies so great small jar with tight fitting lid .)
Fill the container with your herb / flower ( dried are stronger scented ) Fresh flowers tend to be a bit more mild .When your jar is full slowly add your carrier oil to cover Herbs / Flowers cover with lid and gently agitate the contains ( Shake) and place the jar in cool place. ( Some infusions you can set on the windows sill and have the rays from Father Sun shine down upon them, if you have one ) Just check periodically for the aroma you desire . When you have reached the desired aroma simply strain and dis-guard herb/ flower and place infused oil into small jar with tight fitting lid/ cork .
( if you use cork make sure there is space between Oil and Cork other wise it will seep through the cork . )
I do this in some necklaces I make .... Aroma therapy before they came out with the felt inserts for necklaces here are a few infused cooking oils I have done . Same basic principle the only difference in these and essential oil is the amount of herbs/flowers used .
When using citrus such as Lemons, Oranges ,Limes etc.You will use the peel only remove as much of the pith as possible it can be bitter . O kay here are some basics on Oil infusions . So what are you doing still sitting here ......GO Infuse SOME Oil !! (lol)