Using data I received, I made that table, however what does it actually mean in terms of my project. How does it help me decide which one has priority, or which one should be done first?
You need to total the weighted score on each project. Assuming the non weighted score on each factor means the degree each project met that factor and the higher the number the better, then your total weighted score will reveal the priority of your projects. The higher the weighted score, the higher the priority.
EDIT to answer question in comments:
The use of a tool like this really serves as an input into the next step of the prioritization analysis, which is more of a subjective set of arguments where the decision makers, using the results of this exercise as an input/guide, would promote and demote based other, more subjective criteria, sometimes even gut feel. So scores that tie or result very close to each other would be subject to this next analytical step in order to resolve.
If you choose to skip that subjective promotion/demotion exercise, then have a rule established before scoring to handle those close or tied scores, such as what @Tob indicated below. You could use a FIFO (first in first out) rule, i.e., the project identified first gets to go. You could use something a bit more silly such as alphabetical order of the name of the project. You could even agree to "flip a coin," if you are in a laid-back environment that would allow such a thing (I would never suggest this if you are dealing with customers/clients).
While this tool appears quantitative, it was built qualitatively. It is precise but has and will always have accuracy or validity issues. It indicates priority or choice but does not TELL you what it is. You still really need to apply that subjective, gut-feel thing to arrive at a rack and stack that you can defend.