ok. I suggest that you visit the FTDNA FAQ page (or Wikipedia sources) and read up about haplogroup R1b and the occurrence of Identical by State vs. Identical by Descent conditions in relation to haplogroups.
Following are some simplified descriptions of these terms :
IBD stands for Identical By Descent. This means the DNA matches because it comes from a common ancestor. IBD can refer to a single mutation or to a segment of DNA. If a mutation or segment of DNA is IBD among a group of people, it comes from a common ancestor.
The Family Finder relationship predictions require a minimum number of results in a row to be identical in order to identify that the segment is likely to be IBD.
IBS stands for Identical By State, meaning the DNA matches by coincidence. When two individuals share numerous individual results without being related, those results are IBS.
Haplogroup R1b members are well-known for having many matches of IBS. This is usually only able to be overcome by additional STR and/or SNP testing.
Your personal research and edification will hopefully resolve your many questions.