If you are dealing with demons you are going to need to form a summoning circle using sigils to seal and inside that circle draw the sigil of the demon you are trying to summon, you are going to nee to make a blood sacrifice though, try this spell:
(name of demon) I summon thee,
I call upon thee,
Enter this circle,
Make your presence known,
Cross the great divide,
And show me thy ill divined form,
Mote it be
N.B make sure the circle is sealed and do not accept any boons from the demon you summon, and don't try to summon Lucifer, he is way to powerful.
P.S pinterest has the summoning sigils, all you have to do is search sigils and it will show up as thirteen demons and their sigils of summoning.
Good luck and gods bless