A cell group's definition is part of a larger whole, but you can still start a Bible study group in your home! Many people did this long before the term "cells" was used.
The premises for your particular group need to be established, bc there will be stronger members who steer it toward what they want. So you set the terms of format, scheduling, etc.
For instance, you might want an even balance of prayer, Bible study, music/worship, and sharing what's going on in people's lives. Tell people that's what to expect, and that you will need help keeping that on track.
Some groups have a stronger emphasis on counsel and personal support... that tends to get messy and intrusive if overdone.
Some groups will include prophetic elements, encouraging the sharing of dreams, prophecies, administering healing, exorcism. When doing that, be clear with people before they join.
I like Bible studies where everyone shares what they get out of the verses, and bring in background from other sources. Some groups have one teacher, and that can stifle growth of the others members -- always depending on someone to lead them. You can have effective shared Bible studies with new believers -- just use policies similar to the forum here, that only Christianity is promoted. Keep one person as a facilitator (you), so there is always a final say, someone who steers conversation back on track.
Don't leave out group prayer. That is so important.