I recommend you add one column to your spreadsheet so you can enter the name of the common ancestor you share with your match.
The segment bar chart (as the tree graphic) include only a portion of the people you match. (This is a Beta tool.)
Pretend you are looking at a ruler with a segment laying on top. This ruler is divided into centemorgans (cM). The "from" and "to" is the position where you and your matches measurement starts and ends.
Every Match with overlapping segments in a TG will have a Common Ancestor – an ancestor who passed the DNA segment to each of them. Which ancestor you all share is determined by genealogy.-Jim Bartlett
The gray areas indicate a break where a new chromosome begins.