People with OCD usually have a thought that gives them anxiety, then they will use rituals to help relieve that anxiety. It only works for a moment and then you're back at it again. People with OCD tend to avoid things that give them anxiety (triggers) when they're faced with these triggers they use rituals to bring the anxiety down. With ERP you're going to face these triggers without using rituals so you can feel the anxiety go down on its own.
First what you want to do is write down what I call an anxiety ladder. Write down what triggers give you the least amount of anxiety to the most, and rate it through 1-10, 1 being very little and 10 an anxiety attack. For an example when I was dealing with HOCD my highest was an 8, and it was watching coming out videos on YouTube. My lowest was a 2 and it was looking at male models online to show that I don't have an attraction to them.
Once you got your anxiety ladder is complete you're going to face these triggers without doing compulsions and we usually like to take it a step further. An example would be looking at male models, once I saw all those images I got anxiety. I resisted the ritual and scrolled through the whole page slowly to look at every single one. To take it a step further I went on to the second page and said to myself they're attractive but that doesn't mean I'm sexually attracted to them. Before you close your browser or whatever you're using, you need to wait until the anxiety goes down on its own. If you stop viewing the trigger while the anxiety is still at its peak it wont work, and if you use your rituals it wont work either.
Finally once you repeat this process you will start to feel less and less anxiety with the triggers. Try doing one once a week until you feel at about a 1. Also 45 minutes a day seems like a good time frame for most people. Eventually it will become easier and easier to do, and the anxiety will go down faster. It will be extremely hard in the beginning to do. PM me if you need anymore help or explaining. Good luck!