Creating a composite score from dataset with no target variable
If you dont have the outcome of the observation, it is not possible to find which variables are more important (important to predict what ? the « what » is the target value). 

I encourage you to gather some records (20 times the number of features is a good starting point) with targets so the algorithm can understand what features are relevant to the specific outcome you want.

However it is already possible to calculate correlations between variables and do some data analysis to understand how much variance each feature contains.