You also have to supply the energetic form for him to manifest through. I would recommend reading Franz Bardon’s books as they give a lot of techniques and insights.
For now work on silencing the mind and attaining a deep state of relaxation and trance.
This evocation method is an astral/mental evocation and requires you to perfectly memorize the sigil and enn if you choose to use that. So memorize them and once you have that down sit in a comfortable spot in full or half lotus and attain the deepest trance you can slowing down your breathing and heart rate and focus on everything being made of energy.
At that point draw the energy into yourself with each breath condensing it into your body and aura. Once you have collected a lot cast a circle around yourself picturing it rising and surrounding you in a perfect sphere of light and perform the LBRP. Don’t change your physical position simply visualize yourself in your mind facing the directions needed and making the gestures.
From there cast a triangle outside your circle and visualize the sigil made from energy standing up within it. Gather more energy to yourself and project it into the space within the triangle until it is full of power and start the chanting the enn and mentally focusing on the spirit you wish and connecting with them using their sigil as a gate to pull their energy through and they should answer the call relatively quickly. Let the images change as they will and soon the sigil and energy in the triangle should change of their own accord and take on a form and you will communicate in that mental/astral space you have created.
To turn this into a physical evocation after some practice simply project everything you do into the physical space around you instead of the internal temple you have created. This can take anywhere between half an hour to a couple hours depending on your skill and how long it takes you to reach the trance and gather the energy.