When you start using Sigasi, the first thing you have to do is set up a Sigasi project. This consists of two steps: (1) selecting the VHDL files that you want in your project and (2) configuring in which VHDL library these files must be mapped. In most cases you already have this information in one form or another.
The upcoming Sigasi 2.9 will contain a brand new scoping framework. This scoping framework is core functionality of Sigasi that links identifiers with the correct declaration. In the older versions, we had some problems with "overloadable" names and record element names. This made it very hard to fix certain bugs (such as ticket 1196 and ticket 1650).