After being approved for Supplemental security income (SSI). How are monthly payments calculated ?

I recently lost all capabilities of working from degenerative discs in the lower back,and hip arthritis.So anyway I was being helped by a close family member with paying bills, and what not. And now they can longer keep helping me! The great thing is I have just been approved for Supplemental security income (SSI).Not to be confused with SSD! They asked me to send in all the bills I was helped with past, and present. Are they going to reduce any payments because a family member helped me by saying since they have helped pay your bills in the past they need to continue on paying all, or certain ones? I have people saying all types of dumb things like you should say you have been collecting bottles and, that is how you pay your bills, and nothing else! Otherwise you going to receive little or no financial help from them! I find that advice ridiculous! How can I separate what is fact,and what is fiction on how payments are calculated ? Or is there a just a fixed amount that is set to help pay every ones basic needs! And they are just trying to calculate what more I might be helped with ! If any one knows how this all works! Please help me! Thank you!