There isnt really a dogmatic prayer you must follow. Just meditate, focus to Their sigils and speak to them. Be respectful and kind and everything will work.
When there is no wine in my house, I use water. The gods will not be angry with you for that. On the contrary, they will be happy to see your effort, your desire to serve them better. That's what I think.
If there is no bell, you can use your index finger and chant the mantra 'aum' at every turn.